xref: /frameworks/base/core/java/android/webkit/WebView.java

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.webkit;

import android.annotation.Widget;
import android.app.ActivityManager;
import android.app.AlertDialog;
import android.content.BroadcastReceiver;
import android.content.ClipData;
import android.content.ClipboardManager;
import android.content.ComponentCallbacks2;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnCancelListener;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.database.DataSetObserver;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.DrawFilter;
import android.graphics.Paint;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.Picture;
import android.graphics.Point;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Region;
import android.graphics.RegionIterator;
import android.graphics.Shader;
import android.graphics.drawable.Drawable;
import android.net.Proxy;
import android.net.ProxyProperties;
import android.net.Uri;
import android.net.http.SslCertificate;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.StrictMode;
import android.os.SystemClock;
import android.provider.Settings;
import android.speech.tts.TextToSpeech;
import android.text.Editable;
import android.text.InputType;
import android.text.Selection;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.EventLog;
import android.util.Log;
import android.view.Display;
import android.view.Gravity;
import android.view.HapticFeedbackConstants;
import android.view.HardwareCanvas;
import android.view.InputDevice;
import android.view.KeyCharacterMap;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.SoundEffectConstants;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.ViewTreeObserver;
import android.view.WindowManager;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityManager;
import android.view.accessibility.AccessibilityNodeInfo;
import android.view.inputmethod.BaseInputConnection;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputConnection;
import android.view.inputmethod.InputMethodManager;
import android.webkit.WebTextView.AutoCompleteAdapter;
import android.webkit.WebViewCore.DrawData;
import android.webkit.WebViewCore.EventHub;
import android.webkit.WebViewCore.TouchEventData;
import android.webkit.WebViewCore.TouchHighlightData;
import android.webkit.WebViewCore.WebKitHitTest;
import android.widget.AbsoluteLayout;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.CheckedTextView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.OverScroller;
import android.widget.Toast;

import junit.framework.Assert;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Vector;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * <p>A View that displays web pages. This class is the basis upon which you
 * can roll your own web browser or simply display some online content within your Activity.
 * It uses the WebKit rendering engine to display
 * web pages and includes methods to navigate forward and backward
 * through a history, zoom in and out, perform text searches and more.</p>
 * <p>To enable the built-in zoom, set
 * {@link #getSettings() WebSettings}.{@link WebSettings#setBuiltInZoomControls(boolean)}
 * (introduced in API version 3).
 * <p>Note that, in order for your Activity to access the Internet and load web pages
 * in a WebView, you must add the {@code INTERNET} permissions to your
 * Android Manifest file:</p>
 * <pre>&lt;uses-permission android:name="android.permission.INTERNET" /></pre>
 *
 * <p>This must be a child of the <a
 * href="{@docRoot}guide/topics/manifest/manifest-element.html">{@code <manifest>}</a>
 * element.</p>
 *
 * <p>See the <a href="{@docRoot}resources/tutorials/views/hello-webview.html">Web View
 * tutorial</a>.</p>
 *
 * <h3>Basic usage</h3>
 *
 * <p>By default, a WebView provides no browser-like widgets, does not
 * enable JavaScript and web page errors are ignored. If your goal is only
 * to display some HTML as a part of your UI, this is probably fine;
 * the user won't need to interact with the web page beyond reading
 * it, and the web page won't need to interact with the user. If you
 * actually want a full-blown web browser, then you probably want to
 * invoke the Browser application with a URL Intent rather than show it
 * with a WebView. For example:
 * <pre>
 * Uri uri = Uri.parse("http://www.example.com");
 * Intent intent = new Intent(Intent.ACTION_VIEW, uri);
 * startActivity(intent);
 * </pre>
 * <p>See {@link android.content.Intent} for more information.</p>
 *
 * <p>To provide a WebView in your own Activity, include a {@code <WebView>} in your layout,
 * or set the entire Activity window as a WebView during {@link
 * android.app.Activity#onCreate(Bundle) onCreate()}:</p>
 * <pre class="prettyprint">
 * WebView webview = new WebView(this);
 * setContentView(webview);
 * </pre>
 *
 * <p>Then load the desired web page:</p>
 * <pre>
 * // Simplest usage: note that an exception will NOT be thrown
 * // if there is an error loading this page (see below).
 * webview.loadUrl("http://slashdot.org/");
 *
 * // OR, you can also load from an HTML string:
 * String summary = "&lt;html>&lt;body>You scored &lt;b>192&lt;/b> points.&lt;/body>&lt;/html>";
 * webview.loadData(summary, "text/html", null);
 * // ... although note that there are restrictions on what this HTML can do.
 * // See the JavaDocs for {@link #loadData(String,String,String) loadData()} and {@link
 * #loadDataWithBaseURL(String,String,String,String,String) loadDataWithBaseURL()} for more info.
 * </pre>
 *
 * <p>A WebView has several customization points where you can add your
 * own behavior. These are:</p>
 *
 * <ul>
 *   <li>Creating and setting a {@link android.webkit.WebChromeClient} subclass.
 *       This class is called when something that might impact a
 *       browser UI happens, for instance, progress updates and
 *       JavaScript alerts are sent here (see <a
 * href="{@docRoot}guide/developing/debug-tasks.html#DebuggingWebPages">Debugging Tasks</a>).
 *   </li>
 *   <li>Creating and setting a {@link android.webkit.WebViewClient} subclass.
 *       It will be called when things happen that impact the
 *       rendering of the content, eg, errors or form submissions. You
 *       can also intercept URL loading here (via {@link
 * android.webkit.WebViewClient#shouldOverrideUrlLoading(WebView,String)
 * shouldOverrideUrlLoading()}).</li>
 *   <li>Modifying the {@link android.webkit.WebSettings}, such as
 * enabling JavaScript with {@link android.webkit.WebSettings#setJavaScriptEnabled(boolean)
 * setJavaScriptEnabled()}. </li>
 *   <li>Injecting Java objects into the WebView using the
 *       {@link android.webkit.WebView#addJavascriptInterface} method. This
 *       method allows you to inject Java objects into a page's JavaScript
 *       context, so that they can be accessed by JavaScript in the page.</li>
 * </ul>
 *
 * <p>Here's a more complicated example, showing error handling,
 *    settings, and progress notification:</p>
 *
 * <pre class="prettyprint">
 * // Let's display the progress in the activity title bar, like the
 * // browser app does.
 * getWindow().requestFeature(Window.FEATURE_PROGRESS);
 *
 * webview.getSettings().setJavaScriptEnabled(true);
 *
 * final Activity activity = this;
 * webview.setWebChromeClient(new WebChromeClient() {
 *   public void onProgressChanged(WebView view, int progress) {
 *     // Activities and WebViews measure progress with different scales.
 *     // The progress meter will automatically disappear when we reach 100%
 *     activity.setProgress(progress * 1000);
 *   }
 * });
 * webview.setWebViewClient(new WebViewClient() {
 *   public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
 *     Toast.makeText(activity, "Oh no! " + description, Toast.LENGTH_SHORT).show();
 *   }
 * });
 *
 * webview.loadUrl("http://slashdot.org/");
 * </pre>
 *
 * <h3>Cookie and window management</h3>
 *
 * <p>For obvious security reasons, your application has its own
 * cache, cookie store etc.&mdash;it does not share the Browser
 * application's data. Cookies are managed on a separate thread, so
 * operations like index building don't block the UI
 * thread. Follow the instructions in {@link android.webkit.CookieSyncManager}
 * if you want to use cookies in your application.
 * </p>
 *
 * <p>By default, requests by the HTML to open new windows are
 * ignored. This is true whether they be opened by JavaScript or by
 * the target attribute on a link. You can customize your
 * {@link WebChromeClient} to provide your own behaviour for opening multiple windows,
 * and render them in whatever manner you want.</p>
 *
 * <p>The standard behavior for an Activity is to be destroyed and
 * recreated when the device orientation or any other configuration changes. This will cause
 * the WebView to reload the current page. If you don't want that, you
 * can set your Activity to handle the {@code orientation} and {@code keyboardHidden}
 * changes, and then just leave the WebView alone. It'll automatically
 * re-orient itself as appropriate. Read <a
 * href="{@docRoot}guide/topics/resources/runtime-changes.html">Handling Runtime Changes</a> for
 * more information about how to handle configuration changes during runtime.</p>
 *
 *
 * <h3>Building web pages to support different screen densities</h3>
 *
 * <p>The screen density of a device is based on the screen resolution. A screen with low density
 * has fewer available pixels per inch, where a screen with high density
 * has more &mdash; sometimes significantly more &mdash; pixels per inch. The density of a
 * screen is important because, other things being equal, a UI element (such as a button) whose
 * height and width are defined in terms of screen pixels will appear larger on the lower density
 * screen and smaller on the higher density screen.
 * For simplicity, Android collapses all actual screen densities into three generalized densities:
 * high, medium, and low.</p>
 * <p>By default, WebView scales a web page so that it is drawn at a size that matches the default
 * appearance on a medium density screen. So, it applies 1.5x scaling on a high density screen
 * (because its pixels are smaller) and 0.75x scaling on a low density screen (because its pixels
 * are bigger).
 * Starting with API Level 5 (Android 2.0), WebView supports DOM, CSS, and meta tag features to help
 * you (as a web developer) target screens with different screen densities.</p>
 * <p>Here's a summary of the features you can use to handle different screen densities:</p>
 * <ul>
 * <li>The {@code window.devicePixelRatio} DOM property. The value of this property specifies the
 * default scaling factor used for the current device. For example, if the value of {@code
 * window.devicePixelRatio} is "1.0", then the device is considered a medium density (mdpi) device
 * and default scaling is not applied to the web page; if the value is "1.5", then the device is
 * considered a high density device (hdpi) and the page content is scaled 1.5x; if the
 * value is "0.75", then the device is considered a low density device (ldpi) and the content is
 * scaled 0.75x. However, if you specify the {@code "target-densitydpi"} meta property
 * (discussed below), then you can stop this default scaling behavior.</li>
 * <li>The {@code -webkit-device-pixel-ratio} CSS media query. Use this to specify the screen
 * densities for which this style sheet is to be used. The corresponding value should be either
 * "0.75", "1", or "1.5", to indicate that the styles are for devices with low density, medium
 * density, or high density screens, respectively. For example:
 * <pre>
 * &lt;link rel="stylesheet" media="screen and (-webkit-device-pixel-ratio:1.5)" href="hdpi.css" /&gt;</pre>
 * <p>The {@code hdpi.css} stylesheet is only used for devices with a screen pixel ration of 1.5,
 * which is the high density pixel ratio.</p>
 * </li>
 * <li>The {@code target-densitydpi} property for the {@code viewport} meta tag. You can use
 * this to specify the target density for which the web page is designed, using the following
 * values:
 * <ul>
 * <li>{@code device-dpi} - Use the device's native dpi as the target dpi. Default scaling never
 * occurs.</li>
 * <li>{@code high-dpi} - Use hdpi as the target dpi. Medium and low density screens scale down
 * as appropriate.</li>
 * <li>{@code medium-dpi} - Use mdpi as the target dpi. High density screens scale up and
 * low density screens scale down. This is also the default behavior.</li>
 * <li>{@code low-dpi} - Use ldpi as the target dpi. Medium and high density screens scale up
 * as appropriate.</li>
 * <li><em>{@code <value>}</em> - Specify a dpi value to use as the target dpi (accepted
 * values are 70-400).</li>
 * </ul>
 * <p>Here's an example meta tag to specify the target density:</p>
 * <pre>&lt;meta name="viewport" content="target-densitydpi=device-dpi" /&gt;</pre></li>
 * </ul>
 * <p>If you want to modify your web page for different densities, by using the {@code
 * -webkit-device-pixel-ratio} CSS media query and/or the {@code
 * window.devicePixelRatio} DOM property, then you should set the {@code target-densitydpi} meta
 * property to {@code device-dpi}. This stops Android from performing scaling in your web page and
 * allows you to make the necessary adjustments for each density via CSS and JavaScript.</p>
 *
 * <h3>HTML5 Video support</h3>
 *
 * <p>In order to support inline HTML5 video in your application, you need to have hardware
 * acceleration turned on, and set a {@link android.webkit.WebChromeClient}. For full screen support,
 * implementations of {@link WebChromeClient#onShowCustomView(View, WebChromeClient.CustomViewCallback)}
 * and {@link WebChromeClient#onHideCustomView()} are required,
 * {@link WebChromeClient#getVideoLoadingProgressView()} is optional.
 * </p>
 *
 *
 */
@Widget
public class WebView extends AbsoluteLayout
        implements ViewTreeObserver.OnGlobalFocusChangeListener,
        ViewGroup.OnHierarchyChangeListener {

    private class InnerGlobalLayoutListener implements ViewTreeObserver.OnGlobalLayoutListener {
        @Override
        public void onGlobalLayout() {
            if (isShown()) {
                setGLRectViewport();
            }
        }
    }

    private class InnerScrollChangedListener implements ViewTreeObserver.OnScrollChangedListener {
        @Override
        public void onScrollChanged() {
            if (isShown()) {
                setGLRectViewport();
            }
        }
    }

    /**
     * InputConnection used for ContentEditable. This captures changes
     * to the text and sends them either as key strokes or text changes.
     */
    private class WebViewInputConnection extends BaseInputConnection {
        // Used for mapping characters to keys typed.
        private KeyCharacterMap mKeyCharacterMap;
        private boolean mIsKeySentByMe;

        public WebViewInputConnection() {
            super(WebView.this, true);
        }

        @Override
        public boolean sendKeyEvent(KeyEvent event) {
            // Latin IME occasionally sends delete codes directly using
            // sendKeyEvents. WebViewInputConnection should treat this
            // as a deleteSurroundingText.
            if (!mIsKeySentByMe
                    && event.getKeyCode() == KeyEvent.KEYCODE_DEL) {
                Editable editable = getEditable();
                int selectionStart = Selection.getSelectionStart(editable);
                int selectionEnd = Selection.getSelectionEnd(editable);
                if (selectionEnd > 0 && (selectionStart == selectionEnd)) {
                    int action = event.getAction();
                    if (action == KeyEvent.ACTION_UP) {
                        return deleteSurroundingText(1, 0);
                    } else if (action == KeyEvent.ACTION_DOWN) {
                        return true; // the delete will happen in ACTION_UP
                    }
                }
            }
            return super.sendKeyEvent(event);
        }

        public void setTextAndKeepSelection(CharSequence text) {
            Editable editable = getEditable();
            int selectionStart = Selection.getSelectionStart(editable);
            int selectionEnd = Selection.getSelectionEnd(editable);
            editable.replace(0, editable.length(), text);
            InputMethodManager imm = InputMethodManager.peekInstance();
            if (imm != null) {
                // Since the text has changed, do not allow the IME to replace the
                // existing text as though it were a completion.
                imm.restartInput(WebView.this);
            }
            // Keep the previous selection.
            selectionStart = Math.min(selectionStart, editable.length());
            selectionEnd = Math.min(selectionEnd, editable.length());
            setSelection(selectionStart, selectionEnd);
        }

        @Override
        public boolean setComposingText(CharSequence text, int newCursorPosition) {
            Editable editable = getEditable();
            int start = getComposingSpanStart(editable);
            int end = getComposingSpanEnd(editable);
            if (start < 0 || end < 0) {
                start = Selection.getSelectionStart(editable);
                end = Selection.getSelectionEnd(editable);
            }
            if (end < start) {
                int temp = end;
                end = start;
                start = temp;
            }
            setNewText(start, end, text);
            return super.setComposingText(text, newCursorPosition);
        }

        @Override
        public boolean commitText(CharSequence text, int newCursorPosition) {
            setComposingText(text, newCursorPosition);
            int cursorPosition = Selection.getSelectionEnd(getEditable());
            setComposingRegion(cursorPosition, cursorPosition);
            return true;
        }

        @Override
        public boolean deleteSurroundingText(int leftLength, int rightLength) {
            Editable editable = getEditable();
            int cursorPosition = Selection.getSelectionEnd(editable);
            int startDelete = Math.max(0, cursorPosition - leftLength);
            int endDelete = Math.min(editable.length(),
                    cursorPosition + rightLength);
            setNewText(startDelete, endDelete, "");
            return super.deleteSurroundingText(leftLength, rightLength);
        }

        /**
         * Sends a text change to webkit indirectly. If it is a single-
         * character add or delete, it sends it as a key stroke. If it cannot
         * be represented as a key stroke, it sends it as a field change.
         * @param start The start offset (inclusive) of the text being changed.
         * @param end The end offset (exclusive) of the text being changed.
         * @param text The new text to replace the changed text.
         */
        private void setNewText(int start, int end, CharSequence text) {
            mIsKeySentByMe = true;
            Editable editable = getEditable();
            CharSequence original = editable.subSequence(start, end);
            boolean isCharacterAdd = false;
            boolean isCharacterDelete = false;
            int textLength = text.length();
            int originalLength = original.length();
            if (textLength > originalLength) {
                isCharacterAdd = (textLength == originalLength + 1)
                        && TextUtils.regionMatches(text, 0, original, 0,
                                originalLength);
            } else if (originalLength > textLength) {
                isCharacterDelete = (textLength == originalLength - 1)
                        && TextUtils.regionMatches(text, 0, original, 0,
                                textLength);
            }
            if (isCharacterAdd) {
                sendCharacter(text.charAt(textLength - 1));
            } else if (isCharacterDelete) {
                sendDeleteKey();
            } else if (textLength != originalLength ||
                    !TextUtils.regionMatches(text, 0, original, 0,
                            textLength)) {
                // Send a message so that key strokes and text replacement
                // do not come out of order.
                Message replaceMessage = mPrivateHandler.obtainMessage(
                        REPLACE_TEXT, start,  end, text.toString());
                mPrivateHandler.sendMessage(replaceMessage);
            }
            mIsKeySentByMe = false;
        }

        /**
         * Send a single character to the WebView as a key down and up event.
         * @param c The character to be sent.
         */
        private void sendCharacter(char c) {
            if (mKeyCharacterMap == null) {
                mKeyCharacterMap = KeyCharacterMap.load(KeyCharacterMap.VIRTUAL_KEYBOARD);
            }
            char[] chars = new char[1];
            chars[0] = c;
            KeyEvent[] events = mKeyCharacterMap.getEvents(chars);
            if (events != null) {
                for (KeyEvent event : events) {
                    sendKeyEvent(event);
                }
            }
        }

        /**
         * Send the delete character as a key down and up event.
         */
        private void sendDeleteKey() {
            long eventTime = SystemClock.uptimeMillis();
            sendKeyEvent(new KeyEvent(eventTime, eventTime,
                    KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DEL, 0, 0,
                    KeyCharacterMap.VIRTUAL_KEYBOARD, 0,
                    KeyEvent.FLAG_SOFT_KEYBOARD));
            sendKeyEvent(new KeyEvent(SystemClock.uptimeMillis(), eventTime,
                    KeyEvent.ACTION_UP, KeyEvent.KEYCODE_DEL, 0, 0,
                    KeyCharacterMap.VIRTUAL_KEYBOARD, 0,
                    KeyEvent.FLAG_SOFT_KEYBOARD));
        }
    }


    // The listener to capture global layout change event.
    private InnerGlobalLayoutListener mGlobalLayoutListener = null;

    // The listener to capture scroll event.
    private InnerScrollChangedListener mScrollChangedListener = null;

    // if AUTO_REDRAW_HACK is true, then the CALL key will toggle redrawing
    // the screen all-the-time. Good for profiling our drawing code
    static private final boolean AUTO_REDRAW_HACK = false;
    // true means redraw the screen all-the-time. Only with AUTO_REDRAW_HACK
    private boolean mAutoRedraw;

    // Reference to the AlertDialog displayed by InvokeListBox.
    // It's used to dismiss the dialog in destroy if not done before.
    private AlertDialog mListBoxDialog = null;

    static final String LOGTAG = "webview";

    private ZoomManager mZoomManager;

    private final Rect mGLRectViewport = new Rect();
    private final Rect mViewRectViewport = new Rect();
    private final RectF mVisibleContentRect = new RectF();
    private boolean mGLViewportEmpty = false;
    WebViewInputConnection mInputConnection = null;
    private int mFieldPointer;

    /**
     *  Transportation object for returning WebView across thread boundaries.
     */
    public class WebViewTransport {
        private WebView mWebview;

        /**
         * Set the WebView to the transportation object.
         * @param webview The WebView to transport.
         */
        public synchronized void setWebView(WebView webview) {
            mWebview = webview;
        }

        /**
         * Return the WebView object.
         * @return WebView The transported WebView object.
         */
        public synchronized WebView getWebView() {
            return mWebview;
        }
    }

    private static class OnTrimMemoryListener implements ComponentCallbacks2 {
        private static OnTrimMemoryListener sInstance = null;

        static void init(Context c) {
            if (sInstance == null) {
                sInstance = new OnTrimMemoryListener(c.getApplicationContext());
            }
        }

        private OnTrimMemoryListener(Context c) {
            c.registerComponentCallbacks(this);
        }

        @Override
        public void onConfigurationChanged(Configuration newConfig) {
            // Ignore
        }

        @Override
        public void onLowMemory() {
            // Ignore
        }

        @Override
        public void onTrimMemory(int level) {
            if (DebugFlags.WEB_VIEW) {
                Log.d("WebView", "onTrimMemory: " + level);
            }
            WebView.nativeOnTrimMemory(level);
        }

    }

    // A final CallbackProxy shared by WebViewCore and BrowserFrame.
    private final CallbackProxy mCallbackProxy;

    private final WebViewDatabase mDatabase;

    // SSL certificate for the main top-level page (if secure)
    private SslCertificate mCertificate;

    // Native WebView pointer that is 0 until the native object has been
    // created.
    private int mNativeClass;
    // This would be final but it needs to be set to null when the WebView is
    // destroyed.
    private WebViewCore mWebViewCore;
    // Handler for dispatching UI messages.
    /* package */ final Handler mPrivateHandler = new PrivateHandler();
    private WebTextView mWebTextView;
    // Used to ignore changes to webkit text that arrives to the UI side after
    // more key events.
    private int mTextGeneration;

    /* package */ void incrementTextGeneration() { mTextGeneration++; }

    // Used by WebViewCore to create child views.
    /* package */ final ViewManager mViewManager;

    // Used to display in full screen mode
    PluginFullScreenHolder mFullScreenHolder;

    /**
     * Position of the last touch event in pixels.
     * Use integer to prevent loss of dragging delta calculation accuracy;
     * which was done in float and converted to integer, and resulted in gradual
     * and compounding touch position and view dragging mismatch.
     */
    private int mLastTouchX;
    private int mLastTouchY;
    private int mStartTouchX;
    private int mStartTouchY;
    private float mAverageAngle;

    /**
     * Time of the last touch event.
     */
    private long mLastTouchTime;

    /**
     * Time of the last time sending touch event to WebViewCore
     */
    private long mLastSentTouchTime;

    /**
     * The minimum elapsed time before sending another ACTION_MOVE event to
     * WebViewCore. This really should be tuned for each type of the devices.
     * For example in Google Map api test case, it takes Dream device at least
     * 150ms to do a full cycle in the WebViewCore by processing a touch event,
     * triggering the layout and drawing the picture. While the same process
     * takes 60+ms on the current high speed device. If we make
     * TOUCH_SENT_INTERVAL too small, there will be multiple touch events sent
     * to WebViewCore queue and the real layout and draw events will be pushed
     * to further, which slows down the refresh rate. Choose 50 to favor the
     * current high speed devices. For Dream like devices, 100 is a better
     * choice. Maybe make this in the buildspec later.
     * (Update 12/14/2010: changed to 0 since current device should be able to
     * handle the raw events and Map team voted to have the raw events too.
     */
    private static final int TOUCH_SENT_INTERVAL = 0;
    private int mCurrentTouchInterval = TOUCH_SENT_INTERVAL;

    /**
     * Helper class to get velocity for fling
     */
    VelocityTracker mVelocityTracker;
    private int mMaximumFling;
    private float mLastVelocity;
    private float mLastVelX;
    private float mLastVelY;

    // The id of the native layer being scrolled.
    private int mCurrentScrollingLayerId;
    private Rect mScrollingLayerRect = new Rect();

    // only trigger accelerated fling if the new velocity is at least
    // MINIMUM_VELOCITY_RATIO_FOR_ACCELERATION times of the previous velocity
    private static final float MINIMUM_VELOCITY_RATIO_FOR_ACCELERATION = 0.2f;

    /**
     * Touch mode
     */
    private int mTouchMode = TOUCH_DONE_MODE;
    private static final int TOUCH_INIT_MODE = 1;
    private static final int TOUCH_DRAG_START_MODE = 2;
    private static final int TOUCH_DRAG_MODE = 3;
    private static final int TOUCH_SHORTPRESS_START_MODE = 4;
    private static final int TOUCH_SHORTPRESS_MODE = 5;
    private static final int TOUCH_DOUBLE_TAP_MODE = 6;
    private static final int TOUCH_DONE_MODE = 7;
    private static final int TOUCH_PINCH_DRAG = 8;
    private static final int TOUCH_DRAG_LAYER_MODE = 9;

    // Whether to forward the touch events to WebCore
    // Can only be set by WebKit via JNI.
    private boolean mForwardTouchEvents = false;

    // Whether to prevent default during touch. The initial value depends on
    // mForwardTouchEvents. If WebCore wants all the touch events, it says yes
    // for touch down. Otherwise UI will wait for the answer of the first
    // confirmed move before taking over the control.
    private static final int PREVENT_DEFAULT_NO = 0;
    private static final int PREVENT_DEFAULT_MAYBE_YES = 1;
    private static final int PREVENT_DEFAULT_NO_FROM_TOUCH_DOWN = 2;
    private static final int PREVENT_DEFAULT_YES = 3;
    private static final int PREVENT_DEFAULT_IGNORE = 4;
    private int mPreventDefault = PREVENT_DEFAULT_IGNORE;

    // true when the touch movement exceeds the slop
    private boolean mConfirmMove;

    // if true, touch events will be first processed by WebCore, if prevent
    // default is not set, the UI will continue handle them.
    private boolean mDeferTouchProcess;

    // to avoid interfering with the current touch events, track them
    // separately. Currently no snapping or fling in the deferred process mode
    private int mDeferTouchMode = TOUCH_DONE_MODE;
    private float mLastDeferTouchX;
    private float mLastDeferTouchY;

    // To keep track of whether the current drag was initiated by a WebTextView,
    // so that we know not to hide the cursor
    boolean mDragFromTextInput;

    // Whether or not to draw the cursor ring.
    private boolean mDrawCursorRing = true;

    // true if onPause has been called (and not onResume)
    private boolean mIsPaused;

    private HitTestResult mInitialHitTestResult;
    private WebKitHitTest mFocusedNode;

    /**
     * Customizable constant
     */
    // pre-computed square of ViewConfiguration.getScaledTouchSlop()
    private int mTouchSlopSquare;
    // pre-computed square of ViewConfiguration.getScaledDoubleTapSlop()
    private int mDoubleTapSlopSquare;
    // pre-computed density adjusted navigation slop
    private int mNavSlop;
    // This should be ViewConfiguration.getTapTimeout()
    // But system time out is 100ms, which is too short for the browser.
    // In the browser, if it switches out of tap too soon, jump tap won't work.
    // In addition, a double tap on a trackpad will always have a duration of
    // 300ms, so this value must be at least that (otherwise we will timeout the
    // first tap and convert it to a long press).
    private static final int TAP_TIMEOUT = 300;
    // This should be ViewConfiguration.getLongPressTimeout()
    // But system time out is 500ms, which is too short for the browser.
    // With a short timeout, it's difficult to treat trigger a short press.
    private static final int LONG_PRESS_TIMEOUT = 1000;
    // needed to avoid flinging after a pause of no movement
    private static final int MIN_FLING_TIME = 250;
    // draw unfiltered after drag is held without movement
    private static final int MOTIONLESS_TIME = 100;
    // The amount of content to overlap between two screens when going through
    // pages with the space bar, in pixels.
    private static final int PAGE_SCROLL_OVERLAP = 24;

    /**
     * These prevent calling requestLayout if either dimension is fixed. This
     * depends on the layout parameters and the measure specs.
     */
    boolean mWidthCanMeasure;
    boolean mHeightCanMeasure;

    // Remember the last dimensions we sent to the native side so we can avoid
    // sending the same dimensions more than once.
    int mLastWidthSent;
    int mLastHeightSent;
    // Since view height sent to webkit could be fixed to avoid relayout, this
    // value records the last sent actual view height.
    int mLastActualHeightSent;

    private int mContentWidth;   // cache of value from WebViewCore
    private int mContentHeight;  // cache of value from WebViewCore

    // Need to have the separate control for horizontal and vertical scrollbar
    // style than the View's single scrollbar style
    private boolean mOverlayHorizontalScrollbar = true;
    private boolean mOverlayVerticalScrollbar = false;

    // our standard speed. this way small distances will be traversed in less
    // time than large distances, but we cap the duration, so that very large
    // distances won't take too long to get there.
    private static final int STD_SPEED = 480;  // pixels per second
    // time for the longest scroll animation
    private static final int MAX_DURATION = 750;   // milliseconds
    private static final int SLIDE_TITLE_DURATION = 500;   // milliseconds

    // Used by OverScrollGlow
    OverScroller mScroller;

    private boolean mInOverScrollMode = false;
    private static Paint mOverScrollBackground;
    private static Paint mOverScrollBorder;

    private boolean mWrapContent;
    private static final int MOTIONLESS_FALSE           = 0;
    private static final int MOTIONLESS_PENDING         = 1;
    private static final int MOTIONLESS_TRUE            = 2;
    private static final int MOTIONLESS_IGNORE          = 3;
    private int mHeldMotionless;

    // An instance for injecting accessibility in WebViews with disabled
    // JavaScript or ones for which no accessibility script exists
    private AccessibilityInjector mAccessibilityInjector;

    // flag indicating if accessibility script is injected so we
    // know to handle Shift and arrows natively first
    private boolean mAccessibilityScriptInjected;

    private Drawable mSelectHandleLeft;
    private Drawable mSelectHandleRight;
    private Rect mSelectCursorBase = new Rect();
    private int mSelectCursorBaseLayerId;
    private Rect mSelectCursorExtent = new Rect();
    private int mSelectCursorExtentLayerId;
    private Rect mSelectDraggingCursor;
    private Point mSelectDraggingOffset = new Point();
    static final int HANDLE_ID_START = 0;
    static final int HANDLE_ID_END = 1;
    static final int HANDLE_ID_BASE = 2;
    static final int HANDLE_ID_EXTENT = 3;

    static boolean sDisableNavcache = false;
    static boolean sEnableWebTextView = false;
    // the color used to highlight the touch rectangles
    static final int HIGHLIGHT_COLOR = 0x6633b5e5;
    // the region indicating where the user touched on the screen
    private Region mTouchHighlightRegion = new Region();
    // the paint for the touch highlight
    private Paint mTouchHightlightPaint = new Paint();
    // debug only
    private static final boolean DEBUG_TOUCH_HIGHLIGHT = true;
    private static final int TOUCH_HIGHLIGHT_ELAPSE_TIME = 2000;
    private Paint mTouchCrossHairColor;
    private int mTouchHighlightX;
    private int mTouchHighlightY;
    private long mTouchHighlightRequested;

    // Basically this proxy is used to tell the Video to update layer tree at
    // SetBaseLayer time and to pause when WebView paused.
    private HTML5VideoViewProxy mHTML5VideoViewProxy;

    // If we are using a set picture, don't send view updates to webkit
    private boolean mBlockWebkitViewMessages = false;

    // cached value used to determine if we need to switch drawing models
    private boolean mHardwareAccelSkia = false;

    /*
     * Private message ids
     */
    private static final int REMEMBER_PASSWORD          = 1;
    private static final int NEVER_REMEMBER_PASSWORD    = 2;
    private static final int SWITCH_TO_SHORTPRESS       = 3;
    private static final int SWITCH_TO_LONGPRESS        = 4;
    private static final int RELEASE_SINGLE_TAP         = 5;
    private static final int REQUEST_FORM_DATA          = 6;
    private static final int DRAG_HELD_MOTIONLESS       = 8;
    private static final int AWAKEN_SCROLL_BARS         = 9;
    private static final int PREVENT_DEFAULT_TIMEOUT    = 10;
    private static final int SCROLL_SELECT_TEXT         = 11;


    private static final int FIRST_PRIVATE_MSG_ID = REMEMBER_PASSWORD;
    private static final int LAST_PRIVATE_MSG_ID = SCROLL_SELECT_TEXT;

    /*
     * Package message ids
     */
    static final int SCROLL_TO_MSG_ID                   = 101;
    static final int NEW_PICTURE_MSG_ID                 = 105;
    static final int UPDATE_TEXT_ENTRY_MSG_ID           = 106;
    static final int WEBCORE_INITIALIZED_MSG_ID         = 107;
    static final int UPDATE_TEXTFIELD_TEXT_MSG_ID       = 108;
    static final int UPDATE_ZOOM_RANGE                  = 109;
    static final int UNHANDLED_NAV_KEY                  = 110;
    static final int CLEAR_TEXT_ENTRY                   = 111;
    static final int UPDATE_TEXT_SELECTION_MSG_ID       = 112;
    static final int SHOW_RECT_MSG_ID                   = 113;
    static final int LONG_PRESS_CENTER                  = 114;
    static final int PREVENT_TOUCH_ID                   = 115;
    static final int WEBCORE_NEED_TOUCH_EVENTS          = 116;
    // obj=Rect in doc coordinates
    static final int INVAL_RECT_MSG_ID                  = 117;
    static final int REQUEST_KEYBOARD                   = 118;
    static final int DO_MOTION_UP                       = 119;
    static final int SHOW_FULLSCREEN                    = 120;
    static final int HIDE_FULLSCREEN                    = 121;
    static final int DOM_FOCUS_CHANGED                  = 122;
    static final int REPLACE_BASE_CONTENT               = 123;
    static final int FORM_DID_BLUR                      = 124;
    static final int RETURN_LABEL                       = 125;
    static final int FIND_AGAIN                         = 126;
    static final int CENTER_FIT_RECT                    = 127;
    static final int REQUEST_KEYBOARD_WITH_SELECTION_MSG_ID = 128;
    static final int SET_SCROLLBAR_MODES                = 129;
    static final int SELECTION_STRING_CHANGED           = 130;
    static final int HIT_TEST_RESULT                    = 131;
    static final int SAVE_WEBARCHIVE_FINISHED           = 132;

    static final int SET_AUTOFILLABLE                   = 133;
    static final int AUTOFILL_COMPLETE                  = 134;

    static final int SELECT_AT                          = 135;
    static final int SCREEN_ON                          = 136;
    static final int ENTER_FULLSCREEN_VIDEO             = 137;
    static final int UPDATE_SELECTION                   = 138;
    static final int UPDATE_ZOOM_DENSITY                = 139;
    static final int EXIT_FULLSCREEN_VIDEO              = 140;

    static final int COPY_TO_CLIPBOARD                  = 141;
    static final int INIT_EDIT_FIELD                    = 142;
    static final int REPLACE_TEXT                       = 143;

    private static final int FIRST_PACKAGE_MSG_ID = SCROLL_TO_MSG_ID;
    private static final int LAST_PACKAGE_MSG_ID = HIT_TEST_RESULT;

    static final String[] HandlerPrivateDebugString = {
        "REMEMBER_PASSWORD", //              = 1;
        "NEVER_REMEMBER_PASSWORD", //        = 2;
        "SWITCH_TO_SHORTPRESS", //           = 3;
        "SWITCH_TO_LONGPRESS", //            = 4;
        "RELEASE_SINGLE_TAP", //             = 5;
        "REQUEST_FORM_DATA", //              = 6;
        "RESUME_WEBCORE_PRIORITY", //        = 7;
        "DRAG_HELD_MOTIONLESS", //           = 8;
        "AWAKEN_SCROLL_BARS", //             = 9;
        "PREVENT_DEFAULT_TIMEOUT", //        = 10;
        "SCROLL_SELECT_TEXT" //              = 11;
    };

    static final String[] HandlerPackageDebugString = {
        "SCROLL_TO_MSG_ID", //               = 101;
        "102", //                            = 102;
        "103", //                            = 103;
        "104", //                            = 104;
        "NEW_PICTURE_MSG_ID", //             = 105;
        "UPDATE_TEXT_ENTRY_MSG_ID", //       = 106;
        "WEBCORE_INITIALIZED_MSG_ID", //     = 107;
        "UPDATE_TEXTFIELD_TEXT_MSG_ID", //   = 108;
        "UPDATE_ZOOM_RANGE", //              = 109;
        "UNHANDLED_NAV_KEY", //              = 110;
        "CLEAR_TEXT_ENTRY", //               = 111;
        "UPDATE_TEXT_SELECTION_MSG_ID", //   = 112;
        "SHOW_RECT_MSG_ID", //               = 113;
        "LONG_PRESS_CENTER", //              = 114;
        "PREVENT_TOUCH_ID", //               = 115;
        "WEBCORE_NEED_TOUCH_EVENTS", //      = 116;
        "INVAL_RECT_MSG_ID", //              = 117;
        "REQUEST_KEYBOARD", //               = 118;
        "DO_MOTION_UP", //                   = 119;
        "SHOW_FULLSCREEN", //                = 120;
        "HIDE_FULLSCREEN", //                = 121;
        "DOM_FOCUS_CHANGED", //              = 122;
        "REPLACE_BASE_CONTENT", //           = 123;
        "FORM_DID_BLUR", //                  = 124;
        "RETURN_LABEL", //                   = 125;
        "FIND_AGAIN", //                     = 126;
        "CENTER_FIT_RECT", //                = 127;
        "REQUEST_KEYBOARD_WITH_SELECTION_MSG_ID", // = 128;
        "SET_SCROLLBAR_MODES", //            = 129;
        "SELECTION_STRING_CHANGED", //       = 130;
        "SET_TOUCH_HIGHLIGHT_RECTS", //      = 131;
        "SAVE_WEBARCHIVE_FINISHED", //       = 132;
        "SET_AUTOFILLABLE", //               = 133;
        "AUTOFILL_COMPLETE", //              = 134;
        "SELECT_AT", //                      = 135;
        "SCREEN_ON", //                      = 136;
        "ENTER_FULLSCREEN_VIDEO", //         = 137;
        "UPDATE_SELECTION", //               = 138;
        "UPDATE_ZOOM_DENSITY" //             = 139;
    };

    // If the site doesn't use the viewport meta tag to specify the viewport,
    // use DEFAULT_VIEWPORT_WIDTH as the default viewport width
    static final int DEFAULT_VIEWPORT_WIDTH = 980;

    // normally we try to fit the content to the minimum preferred width
    // calculated by the Webkit. To avoid the bad behavior when some site's
    // minimum preferred width keeps growing when changing the viewport width or
    // the minimum preferred width is huge, an upper limit is needed.
    static int sMaxViewportWidth = DEFAULT_VIEWPORT_WIDTH;

    // initial scale in percent. 0 means using default.
    private int mInitialScaleInPercent = 0;

    // Whether or not a scroll event should be sent to webkit.  This is only set
    // to false when restoring the scroll position.
    private boolean mSendScrollEvent = true;

    private int mSnapScrollMode = SNAP_NONE;
    private static final int SNAP_NONE = 0;
    private static final int SNAP_LOCK = 1; // not a separate state
    private static final int SNAP_X = 2; // may be combined with SNAP_LOCK
    private static final int SNAP_Y = 4; // may be combined with SNAP_LOCK
    private boolean mSnapPositive;

    // keep these in sync with their counterparts in WebView.cpp
    private static final int DRAW_EXTRAS_NONE = 0;
    private static final int DRAW_EXTRAS_FIND = 1;
    private static final int DRAW_EXTRAS_SELECTION = 2;
    private static final int DRAW_EXTRAS_CURSOR_RING = 3;

    // keep this in sync with WebCore:ScrollbarMode in WebKit
    private static final int SCROLLBAR_AUTO = 0;
    private static final int SCROLLBAR_ALWAYSOFF = 1;
    // as we auto fade scrollbar, this is ignored.
    private static final int SCROLLBAR_ALWAYSON = 2;
    private int mHorizontalScrollBarMode = SCROLLBAR_AUTO;
    private int mVerticalScrollBarMode = SCROLLBAR_AUTO;

    // constants for determining script injection strategy
    private static final int ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED = -1;
    private static final int ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT = 0;
    private static final int ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED = 1;

    // the alias via which accessibility JavaScript interface is exposed
    private static final String ALIAS_ACCESSIBILITY_JS_INTERFACE = "accessibility";

    // Template for JavaScript that injects a screen-reader.
    private static final String ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE =
        "javascript:(function() {" +
        "    var chooser = document.createElement('script');" +
        "    chooser.type = 'text/javascript';" +
        "    chooser.src = '%1s';" +
        "    document.getElementsByTagName('head')[0].appendChild(chooser);" +
        "  })();";

    // Regular expression that matches the "axs" URL parameter.
    // The value of 0 means the accessibility script is opted out
    // The value of 1 means the accessibility script is already injected
    private static final String PATTERN_MATCH_AXS_URL_PARAMETER = "(\\?axs=(0|1))|(&axs=(0|1))";

    // TextToSpeech instance exposed to JavaScript to the injected screenreader.
    private TextToSpeech mTextToSpeech;

    // variable to cache the above pattern in case accessibility is enabled.
    private Pattern mMatchAxsUrlParameterPattern;

    /**
     * Max distance to overscroll by in pixels.
     * This how far content can be pulled beyond its normal bounds by the user.
     */
    private int mOverscrollDistance;

    /**
     * Max distance to overfling by in pixels.
     * This is how far flinged content can move beyond the end of its normal bounds.
     */
    private int mOverflingDistance;

    private OverScrollGlow mOverScrollGlow;

    // Used to match key downs and key ups
    private Vector<Integer> mKeysPressed;

    /* package */ static boolean mLogEvent = true;

    // for event log
    private long mLastTouchUpTime = 0;

    private WebViewCore.AutoFillData mAutoFillData;

    private static boolean sNotificationsEnabled = true;

    /**
     * URI scheme for telephone number
     */
    public static final String SCHEME_TEL = "tel:";
    /**
     * URI scheme for email address
     */
    public static final String SCHEME_MAILTO = "mailto:";
    /**
     * URI scheme for map address
     */
    public static final String SCHEME_GEO = "geo:0,0?q=";

    private int mBackgroundColor = Color.WHITE;

    private static final long SELECT_SCROLL_INTERVAL = 1000 / 60; // 60 / second
    private int mAutoScrollX = 0;
    private int mAutoScrollY = 0;
    private int mMinAutoScrollX = 0;
    private int mMaxAutoScrollX = 0;
    private int mMinAutoScrollY = 0;
    private int mMaxAutoScrollY = 0;
    private Rect mScrollingLayerBounds = new Rect();
    private boolean mSentAutoScrollMessage = false;

    // used for serializing asynchronously handled touch events.
    private final TouchEventQueue mTouchEventQueue = new TouchEventQueue();

    // Used to track whether picture updating was paused due to a window focus change.
    private boolean mPictureUpdatePausedForFocusChange = false;

    // Used to notify listeners of a new picture.
    private PictureListener mPictureListener;
    /**
     * Interface to listen for new pictures as they change.
     * @deprecated This interface is now obsolete.
     */
    @Deprecated
    public interface PictureListener {
        /**
         * Notify the listener that the picture has changed.
         * @param view The WebView that owns the picture.
         * @param picture The new picture.
         * @deprecated Due to internal changes, the picture does not include
         * composited layers such as fixed position elements or scrollable divs.
         * While the PictureListener API can still be used to detect changes in
         * the WebView content, you are advised against its usage until a replacement
         * is provided in a future Android release
         */
        @Deprecated
        public void onNewPicture(WebView view, Picture picture);
    }

    public static class HitTestResult {
        /**
         * Default HitTestResult, where the target is unknown
         */
        public static final int UNKNOWN_TYPE = 0;
        /**
         * @deprecated This type is no longer used.
         */
        @Deprecated
        public static final int ANCHOR_TYPE = 1;
        /**
         * HitTestResult for hitting a phone number
         */
        public static final int PHONE_TYPE = 2;
        /**
         * HitTestResult for hitting a map address
         */
        public static final int GEO_TYPE = 3;
        /**
         * HitTestResult for hitting an email address
         */
        public static final int EMAIL_TYPE = 4;
        /**
         * HitTestResult for hitting an HTML::img tag
         */
        public static final int IMAGE_TYPE = 5;
        /**
         * @deprecated This type is no longer used.
         */
        @Deprecated
        public static final int IMAGE_ANCHOR_TYPE = 6;
        /**
         * HitTestResult for hitting a HTML::a tag with src=http
         */
        public static final int SRC_ANCHOR_TYPE = 7;
        /**
         * HitTestResult for hitting a HTML::a tag with src=http + HTML::img
         */
        public static final int SRC_IMAGE_ANCHOR_TYPE = 8;
        /**
         * HitTestResult for hitting an edit text area
         */
        public static final int EDIT_TEXT_TYPE = 9;

        private int mType;
        private String mExtra;

        HitTestResult() {
            mType = UNKNOWN_TYPE;
        }

        private void setType(int type) {
            mType = type;
        }

        private void setExtra(String extra) {
            mExtra = extra;
        }

        /**
         * Gets the type of the hit test result.
         * @return See the XXX_TYPE constants defined in this class.
         */
        public int getType() {
            return mType;
        }

        /**
         * Gets additional type-dependant information about the result, see
         * {@link WebView#getHitTestResult()} for details.
         * @return may either be null or contain extra information about this result.
         */
        public String getExtra() {
            return mExtra;
        }
    }

    /**
     * Refer to {@link WebView#requestFocusNodeHref(Message)} for more information
     */
    static class FocusNodeHref {
        static final String TITLE = "title";
        static final String URL = "url";
        static final String SRC = "src";
    }

    /**
     * Construct a new WebView with a Context object.
     * @param context A Context object used to access application assets.
     */
    public WebView(Context context) {
        this(context, null);
    }

    /**
     * Construct a new WebView with layout parameters.
     * @param context A Context object used to access application assets.
     * @param attrs An AttributeSet passed to our parent.
     */
    public WebView(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.webViewStyle);
    }

    /**
     * Construct a new WebView with layout parameters and a default style.
     * @param context A Context object used to access application assets.
     * @param attrs An AttributeSet passed to our parent.
     * @param defStyle The default style resource ID.
     */
    public WebView(Context context, AttributeSet attrs, int defStyle) {
        this(context, attrs, defStyle, false);
    }

    /**
     * Construct a new WebView with layout parameters and a default style.
     * @param context A Context object used to access application assets.
     * @param attrs An AttributeSet passed to our parent.
     * @param defStyle The default style resource ID.
     * @param privateBrowsing If true the web view will be initialized in private mode.
     */
    public WebView(Context context, AttributeSet attrs, int defStyle,
            boolean privateBrowsing) {
        this(context, attrs, defStyle, null, privateBrowsing);
    }

    /**
     * Construct a new WebView with layout parameters, a default style and a set
     * of custom Javscript interfaces to be added to the WebView at initialization
     * time. This guarantees that these interfaces will be available when the JS
     * context is initialized.
     * @param context A Context object used to access application assets.
     * @param attrs An AttributeSet passed to our parent.
     * @param defStyle The default style resource ID.
     * @param javaScriptInterfaces is a Map of interface names, as keys, and
     * object implementing those interfaces, as values.
     * @param privateBrowsing If true the web view will be initialized in private mode.
     * @hide This is an implementation detail.
     */
    protected WebView(Context context, AttributeSet attrs, int defStyle,
            Map<String, Object> javaScriptInterfaces, boolean privateBrowsing) {
        super(context, attrs, defStyle);
        checkThread();

        if (context == null) {
            throw new IllegalArgumentException("Invalid context argument");
        }

        // Used by the chrome stack to find application paths
        JniUtil.setContext(context);

        mCallbackProxy = new CallbackProxy(context, this);
        mViewManager = new ViewManager(this);
        L10nUtils.setApplicationContext(context.getApplicationContext());
        mWebViewCore = new WebViewCore(context, this, mCallbackProxy, javaScriptInterfaces);
        mDatabase = WebViewDatabase.getInstance(context);
        mScroller = new OverScroller(context, null, 0, 0, false); //TODO Use OverScroller's flywheel
        mZoomManager = new ZoomManager(this, mCallbackProxy);

        /* The init method must follow the creation of certain member variables,
         * such as the mZoomManager.
         */
        init();
        setupPackageListener(context);
        setupProxyListener(context);
        updateMultiTouchSupport(context);

        if (privateBrowsing) {
            startPrivateBrowsing();
        }

        mAutoFillData = new WebViewCore.AutoFillData();
    }

    private static class ProxyReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            if (intent.getAction().equals(Proxy.PROXY_CHANGE_ACTION)) {
                handleProxyBroadcast(intent);
            }
        }
    }

    /*
     * Receiver for PROXY_CHANGE_ACTION, will be null when it is not added handling broadcasts.
     */
    private static ProxyReceiver sProxyReceiver;

    /*
     * @param context This method expects this to be a valid context
     */
    private static synchronized void setupProxyListener(Context context) {
        if (sProxyReceiver != null || sNotificationsEnabled == false) {
            return;
        }
        IntentFilter filter = new IntentFilter();
        filter.addAction(Proxy.PROXY_CHANGE_ACTION);
        sProxyReceiver = new ProxyReceiver();
        Intent currentProxy = context.getApplicationContext().registerReceiver(
                sProxyReceiver, filter);
        if (currentProxy != null) {
            handleProxyBroadcast(currentProxy);
        }
    }

    /*
     * @param context This method expects this to be a valid context
     */
    private static synchronized void disableProxyListener(Context context) {
        if (sProxyReceiver == null)
            return;

        context.getApplicationContext().unregisterReceiver(sProxyReceiver);
        sProxyReceiver = null;
    }

    private static void handleProxyBroadcast(Intent intent) {
        ProxyProperties proxyProperties = (ProxyProperties)intent.getExtra(Proxy.EXTRA_PROXY_INFO);
        if (proxyProperties == null || proxyProperties.getHost() == null) {
            WebViewCore.sendStaticMessage(EventHub.PROXY_CHANGED, null);
            return;
        }
        WebViewCore.sendStaticMessage(EventHub.PROXY_CHANGED, proxyProperties);
    }

    /*
     * A variable to track if there is a receiver added for ACTION_PACKAGE_ADDED
     * or ACTION_PACKAGE_REMOVED.
     */
    private static boolean sPackageInstallationReceiverAdded = false;

    /*
     * A set of Google packages we monitor for the
     * navigator.isApplicationInstalled() API. Add additional packages as
     * needed.
     */
    private static Set<String> sGoogleApps;
    static {
        sGoogleApps = new HashSet<String>();
        sGoogleApps.add("com.google.android.youtube");
    }

    private static class PackageListener extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            final String action = intent.getAction();
            final String packageName = intent.getData().getSchemeSpecificPart();
            final boolean replacing = intent.getBooleanExtra(Intent.EXTRA_REPLACING, false);
            if (Intent.ACTION_PACKAGE_REMOVED.equals(action) && replacing) {
                // if it is replacing, refreshPlugins() when adding
                return;
            }

            if (sGoogleApps.contains(packageName)) {
                if (Intent.ACTION_PACKAGE_ADDED.equals(action)) {
                    WebViewCore.sendStaticMessage(EventHub.ADD_PACKAGE_NAME, packageName);
                } else {
                    WebViewCore.sendStaticMessage(EventHub.REMOVE_PACKAGE_NAME, packageName);
                }
            }

            PluginManager pm = PluginManager.getInstance(context);
            if (pm.containsPluginPermissionAndSignatures(packageName)) {
                pm.refreshPlugins(Intent.ACTION_PACKAGE_ADDED.equals(action));
            }
        }
    }

    private void setupPackageListener(Context context) {

        /*
         * we must synchronize the instance check and the creation of the
         * receiver to ensure that only ONE receiver exists for all WebView
         * instances.
         */
        synchronized (WebView.class) {

            // if the receiver already exists then we do not need to register it
            // again
            if (sPackageInstallationReceiverAdded) {
                return;
            }

            IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
            filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
            filter.addDataScheme("package");
            BroadcastReceiver packageListener = new PackageListener();
            context.getApplicationContext().registerReceiver(packageListener, filter);
            sPackageInstallationReceiverAdded = true;
        }

        // check if any of the monitored apps are already installed
        AsyncTask<Void, Void, Set<String>> task = new AsyncTask<Void, Void, Set<String>>() {

            @Override
            protected Set<String> doInBackground(Void... unused) {
                Set<String> installedPackages = new HashSet<String>();
                PackageManager pm = mContext.getPackageManager();
                for (String name : sGoogleApps) {
                    try {
                        pm.getPackageInfo(name,
                                PackageManager.GET_ACTIVITIES | PackageManager.GET_SERVICES);
                        installedPackages.add(name);
                    } catch (PackageManager.NameNotFoundException e) {
                        // package not found
                    }
                }
                return installedPackages;
            }

            // Executes on the UI thread
            @Override
            protected void onPostExecute(Set<String> installedPackages) {
                if (mWebViewCore != null) {
                    mWebViewCore.sendMessage(EventHub.ADD_PACKAGE_NAMES, installedPackages);
                }
            }
        };
        task.execute();
    }

    void updateMultiTouchSupport(Context context) {
        mZoomManager.updateMultiTouchSupport(context);
    }

    private void init() {
        OnTrimMemoryListener.init(getContext());
        sDisableNavcache = nativeDisableNavcache();
        setWillNotDraw(false);
        setFocusable(true);
        setFocusableInTouchMode(true);
        setClickable(true);
        setLongClickable(true);

        final ViewConfiguration configuration = ViewConfiguration.get(getContext());
        int slop = configuration.getScaledTouchSlop();
        mTouchSlopSquare = slop * slop;
        slop = configuration.getScaledDoubleTapSlop();
        mDoubleTapSlopSquare = slop * slop;
        final float density = getContext().getResources().getDisplayMetrics().density;
        // use one line height, 16 based on our current default font, for how
        // far we allow a touch be away from the edge of a link
        mNavSlop = (int) (16 * density);
        mZoomManager.init(density);
        mMaximumFling = configuration.getScaledMaximumFlingVelocity();

        // Compute the inverse of the density squared.
        DRAG_LAYER_INVERSE_DENSITY_SQUARED = 1 / (density * density);

        mOverscrollDistance = configuration.getScaledOverscrollDistance();
        mOverflingDistance = configuration.getScaledOverflingDistance();

        setScrollBarStyle(super.getScrollBarStyle());
        // Initially use a size of two, since the user is likely to only hold
        // down two keys at a time (shift + another key)
        mKeysPressed = new Vector<Integer>(2);
        mHTML5VideoViewProxy = null ;
    }

    @Override
    public boolean shouldDelayChildPressedState() {
        return true;
    }

    /**
     * Adds accessibility APIs to JavaScript.
     *
     * Note: This method is responsible to performing the necessary
     *       check if the accessibility APIs should be exposed.
     */
    private void addAccessibilityApisToJavaScript() {
        if (AccessibilityManager.getInstance(mContext).isEnabled()
                && getSettings().getJavaScriptEnabled()) {
            // exposing the TTS for now ...
            final Context ctx = getContext();
            if (ctx != null) {
                final String packageName = ctx.getPackageName();
                if (packageName != null) {
                    mTextToSpeech = new TextToSpeech(getContext(), null, null,
                            packageName + ".**webview**", true);
                    addJavascriptInterface(mTextToSpeech, ALIAS_ACCESSIBILITY_JS_INTERFACE);
                }
            }
        }
    }

    /**
     * Removes accessibility APIs from JavaScript.
     */
    private void removeAccessibilityApisFromJavaScript() {
        // exposing the TTS for now ...
        if (mTextToSpeech != null) {
            removeJavascriptInterface(ALIAS_ACCESSIBILITY_JS_INTERFACE);
            mTextToSpeech.shutdown();
            mTextToSpeech = null;
        }
    }

    @Override
    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
        super.onInitializeAccessibilityNodeInfo(info);
        info.setScrollable(isScrollableForAccessibility());
    }

    @Override
    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
        super.onInitializeAccessibilityEvent(event);
        event.setScrollable(isScrollableForAccessibility());
        event.setScrollX(mScrollX);
        event.setScrollY(mScrollY);
        final int convertedContentWidth = contentToViewX(getContentWidth());
        final int adjustedViewWidth = getWidth() - mPaddingLeft - mPaddingRight;
        event.setMaxScrollX(Math.max(convertedContentWidth - adjustedViewWidth, 0));
        final int convertedContentHeight = contentToViewY(getContentHeight());
        final int adjustedViewHeight = getHeight() - mPaddingTop - mPaddingBottom;
        event.setMaxScrollY(Math.max(convertedContentHeight - adjustedViewHeight, 0));
    }

    private boolean isScrollableForAccessibility() {
        return (contentToViewX(getContentWidth()) > getWidth() - mPaddingLeft - mPaddingRight
                || contentToViewY(getContentHeight()) > getHeight() - mPaddingTop - mPaddingBottom);
    }

    @Override
    public void setOverScrollMode(int mode) {
        super.setOverScrollMode(mode);
        if (mode != OVER_SCROLL_NEVER) {
            if (mOverScrollGlow == null) {
                mOverScrollGlow = new OverScrollGlow(this);
            }
        } else {
            mOverScrollGlow = null;
        }
    }

    /* package */ void adjustDefaultZoomDensity(int zoomDensity) {
        final float density = mContext.getResources().getDisplayMetrics().density
                * 100 / zoomDensity;
        updateDefaultZoomDensity(density);
    }

    /* package */ void updateDefaultZoomDensity(float density) {
        mNavSlop = (int) (16 * density);
        mZoomManager.updateDefaultZoomDensity(density);
    }

    /* package */ boolean onSavePassword(String schemePlusHost, String username,
            String password, final Message resumeMsg) {
       boolean rVal = false;
       if (resumeMsg == null) {
           // null resumeMsg implies saving password silently
           mDatabase.setUsernamePassword(schemePlusHost, username, password);
       } else {
            final Message remember = mPrivateHandler.obtainMessage(
                    REMEMBER_PASSWORD);
            remember.getData().putString("host", schemePlusHost);
            remember.getData().putString("username", username);
            remember.getData().putString("password", password);
            remember.obj = resumeMsg;

            final Message neverRemember = mPrivateHandler.obtainMessage(
                    NEVER_REMEMBER_PASSWORD);
            neverRemember.getData().putString("host", schemePlusHost);
            neverRemember.getData().putString("username", username);
            neverRemember.getData().putString("password", password);
            neverRemember.obj = resumeMsg;

            new AlertDialog.Builder(getContext())
                    .setTitle(com.android.internal.R.string.save_password_label)
                    .setMessage(com.android.internal.R.string.save_password_message)
                    .setPositiveButton(com.android.internal.R.string.save_password_notnow,
                    new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            resumeMsg.sendToTarget();
                        }
                    })
                    .setNeutralButton(com.android.internal.R.string.save_password_remember,
                    new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            remember.sendToTarget();
                        }
                    })
                    .setNegativeButton(com.android.internal.R.string.save_password_never,
                    new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            neverRemember.sendToTarget();
                        }
                    })
                    .setOnCancelListener(new OnCancelListener() {
                        @Override
                        public void onCancel(DialogInterface dialog) {
                            resumeMsg.sendToTarget();
                        }
                    }).show();
            // Return true so that WebViewCore will pause while the dialog is
            // up.
            rVal = true;
        }
       return rVal;
    }

    @Override
    public void setScrollBarStyle(int style) {
        if (style == View.SCROLLBARS_INSIDE_INSET
                || style == View.SCROLLBARS_OUTSIDE_INSET) {
            mOverlayHorizontalScrollbar = mOverlayVerticalScrollbar = false;
        } else {
            mOverlayHorizontalScrollbar = mOverlayVerticalScrollbar = true;
        }
        super.setScrollBarStyle(style);
    }

    /**
     * Specify whether the horizontal scrollbar has overlay style.
     * @param overlay TRUE if horizontal scrollbar should have overlay style.
     */
    public void setHorizontalScrollbarOverlay(boolean overlay) {
        checkThread();
        mOverlayHorizontalScrollbar = overlay;
    }

    /**
     * Specify whether the vertical scrollbar has overlay style.
     * @param overlay TRUE if vertical scrollbar should have overlay style.
     */
    public void setVerticalScrollbarOverlay(boolean overlay) {
        checkThread();
        mOverlayVerticalScrollbar = overlay;
    }

    /**
     * Return whether horizontal scrollbar has overlay style
     * @return TRUE if horizontal scrollbar has overlay style.
     */
    public boolean overlayHorizontalScrollbar() {
        checkThread();
        return mOverlayHorizontalScrollbar;
    }

    /**
     * Return whether vertical scrollbar has overlay style
     * @return TRUE if vertical scrollbar has overlay style.
     */
    public boolean overlayVerticalScrollbar() {
        checkThread();
        return mOverlayVerticalScrollbar;
    }

    /*
     * Return the width of the view where the content of WebView should render
     * to.
     * Note: this can be called from WebCoreThread.
     */
    /* package */ int getViewWidth() {
        if (!isVerticalScrollBarEnabled() || mOverlayVerticalScrollbar) {
            return getWidth();
        } else {
            return Math.max(0, getWidth() - getVerticalScrollbarWidth());
        }
    }

    /**
     * returns the height of the titlebarview (if any). Does not care about
     * scrolling
     * @hide
     */
    protected int getTitleHeight() {
        return mTitleBar != null ? mTitleBar.getHeight() : 0;
    }

    /**
     * Return the amount of the titlebarview (if any) that is visible
     *
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public int getVisibleTitleHeight() {
        checkThread();
        return getVisibleTitleHeightImpl();
    }

    private int getVisibleTitleHeightImpl() {
        // need to restrict mScrollY due to over scroll
        return Math.max(getTitleHeight() - Math.max(0, mScrollY),
                getOverlappingActionModeHeight());
    }

    private int mCachedOverlappingActionModeHeight = -1;

    private int getOverlappingActionModeHeight() {
        if (mFindCallback == null) {
            return 0;
        }
        if (mCachedOverlappingActionModeHeight < 0) {
            getGlobalVisibleRect(mGlobalVisibleRect, mGlobalVisibleOffset);
            mCachedOverlappingActionModeHeight = Math.max(0,
                    mFindCallback.getActionModeGlobalBottom() - mGlobalVisibleRect.top);
        }
        return mCachedOverlappingActionModeHeight;
    }

    /*
     * Return the height of the view where the content of WebView should render
     * to.  Note that this excludes mTitleBar, if there is one.
     * Note: this can be called from WebCoreThread.
     */
    /* package */ int getViewHeight() {
        return getViewHeightWithTitle() - getVisibleTitleHeightImpl();
    }

    int getViewHeightWithTitle() {
        int height = getHeight();
        if (isHorizontalScrollBarEnabled() && !mOverlayHorizontalScrollbar) {
            height -= getHorizontalScrollbarHeight();
        }
        return height;
    }

    /**
     * @return The SSL certificate for the main top-level page or null if
     * there is no certificate (the site is not secure).
     */
    public SslCertificate getCertificate() {
        checkThread();
        return mCertificate;
    }

    /**
     * Sets the SSL certificate for the main top-level page.
     */
    public void setCertificate(SslCertificate certificate) {
        checkThread();
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "setCertificate=" + certificate);
        }
        // here, the certificate can be null (if the site is not secure)
        mCertificate = certificate;
    }

    //-------------------------------------------------------------------------
    // Methods called by activity
    //-------------------------------------------------------------------------

    /**
     * Save the username and password for a particular host in the WebView's
     * internal database.
     * @param host The host that required the credentials.
     * @param username The username for the given host.
     * @param password The password for the given host.
     */
    public void savePassword(String host, String username, String password) {
        checkThread();
        mDatabase.setUsernamePassword(host, username, password);
    }

    /**
     * Set the HTTP authentication credentials for a given host and realm.
     *
     * @param host The host for the credentials.
     * @param realm The realm for the credentials.
     * @param username The username for the password. If it is null, it means
     *                 password can't be saved.
     * @param password The password
     */
    public void setHttpAuthUsernamePassword(String host, String realm,
            String username, String password) {
        checkThread();
        mDatabase.setHttpAuthUsernamePassword(host, realm, username, password);
    }

    /**
     * Retrieve the HTTP authentication username and password for a given
     * host & realm pair
     *
     * @param host The host for which the credentials apply.
     * @param realm The realm for which the credentials apply.
     * @return String[] if found, String[0] is username, which can be null and
     *         String[1] is password. Return null if it can't find anything.
     */
    public String[] getHttpAuthUsernamePassword(String host, String realm) {
        checkThread();
        return mDatabase.getHttpAuthUsernamePassword(host, realm);
    }

    /**
     * Remove Find or Select ActionModes, if active.
     */
    private void clearActionModes() {
        if (mSelectCallback != null) {
            mSelectCallback.finish();
        }
        if (mFindCallback != null) {
            mFindCallback.finish();
        }
    }

    /**
     * Called to clear state when moving from one page to another, or changing
     * in some other way that makes elements associated with the current page
     * (such as WebTextView or ActionModes) no longer relevant.
     */
    private void clearHelpers() {
        clearTextEntry();
        clearActionModes();
        dismissFullScreenMode();
        cancelSelectDialog();
    }

    private void cancelSelectDialog() {
        if (mListBoxDialog != null) {
            mListBoxDialog.cancel();
            mListBoxDialog = null;
        }
    }

    /**
     * Destroy the internal state of the WebView. This method should be called
     * after the WebView has been removed from the view system. No other
     * methods may be called on a WebView after destroy.
     */
    public void destroy() {
        checkThread();
        destroyImpl();
    }

    private void destroyImpl() {
        clearHelpers();
        if (mListBoxDialog != null) {
            mListBoxDialog.dismiss();
            mListBoxDialog = null;
        }
        // remove so that it doesn't cause events
        if (mWebTextView != null) {
            mWebTextView.remove();
            mWebTextView = null;
        }
        if (mNativeClass != 0) nativeStopGL();
        if (mWebViewCore != null) {
            // Set the handlers to null before destroying WebViewCore so no
            // more messages will be posted.
            mCallbackProxy.setWebViewClient(null);
            mCallbackProxy.setWebChromeClient(null);
            // Tell WebViewCore to destroy itself
            synchronized (this) {
                WebViewCore webViewCore = mWebViewCore;
                mWebViewCore = null; // prevent using partial webViewCore
                webViewCore.destroy();
            }
            // Remove any pending messages that might not be serviced yet.
            mPrivateHandler.removeCallbacksAndMessages(null);
            mCallbackProxy.removeCallbacksAndMessages(null);
            // Wake up the WebCore thread just in case it is waiting for a
            // JavaScript dialog.
            synchronized (mCallbackProxy) {
                mCallbackProxy.notify();
            }
        }
        if (mNativeClass != 0) {
            nativeDestroy();
            mNativeClass = 0;
        }
    }

    /**
     * Enables platform notifications of data state and proxy changes.
     * Notifications are enabled by default.
     *
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public static void enablePlatformNotifications() {
        checkThread();
        synchronized (WebView.class) {
            Network.enablePlatformNotifications();
            sNotificationsEnabled = true;
            Context context = JniUtil.getContext();
            if (context != null)
                setupProxyListener(context);
        }
    }

    /**
     * Disables platform notifications of data state and proxy changes.
     * Notifications are enabled by default.
     *
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public static void disablePlatformNotifications() {
        checkThread();
        synchronized (WebView.class) {
            Network.disablePlatformNotifications();
            sNotificationsEnabled = false;
            Context context = JniUtil.getContext();
            if (context != null)
                disableProxyListener(context);
        }
    }

    /**
     * Sets JavaScript engine flags.
     *
     * @param flags JS engine flags in a String
     *
     * @hide This is an implementation detail.
     */
    public void setJsFlags(String flags) {
        checkThread();
        mWebViewCore.sendMessage(EventHub.SET_JS_FLAGS, flags);
    }

    /**
     * Inform WebView of the network state. This is used to set
     * the JavaScript property window.navigator.isOnline and
     * generates the online/offline event as specified in HTML5, sec. 5.7.7
     * @param networkUp boolean indicating if network is available
     */
    public void setNetworkAvailable(boolean networkUp) {
        checkThread();
        mWebViewCore.sendMessage(EventHub.SET_NETWORK_STATE,
                networkUp ? 1 : 0, 0);
    }

    /**
     * Inform WebView about the current network type.
     * {@hide}
     */
    public void setNetworkType(String type, String subtype) {
        checkThread();
        Map<String, String> map = new HashMap<String, String>();
        map.put("type", type);
        map.put("subtype", subtype);
        mWebViewCore.sendMessage(EventHub.SET_NETWORK_TYPE, map);
    }
    /**
     * Save the state of this WebView used in
     * {@link android.app.Activity#onSaveInstanceState}. Please note that this
     * method no longer stores the display data for this WebView. The previous
     * behavior could potentially leak files if {@link #restoreState} was never
     * called. See {@link #savePicture} and {@link #restorePicture} for saving
     * and restoring the display data.
     * @param outState The Bundle to store the WebView state.
     * @return The same copy of the back/forward list used to save the state. If
     *         saveState fails, the returned list will be null.
     * @see #savePicture
     * @see #restorePicture
     */
    public WebBackForwardList saveState(Bundle outState) {
        checkThread();
        if (outState == null) {
            return null;
        }
        // We grab a copy of the back/forward list because a client of WebView
        // may have invalidated the history list by calling clearHistory.
        WebBackForwardList list = copyBackForwardList();
        final int currentIndex = list.getCurrentIndex();
        final int size = list.getSize();
        // We should fail saving the state if the list is empty or the index is
        // not in a valid range.
        if (currentIndex < 0 || currentIndex >= size || size == 0) {
            return null;
        }
        outState.putInt("index", currentIndex);
        // FIXME: This should just be a byte[][] instead of ArrayList but
        // Parcel.java does not have the code to handle multi-dimensional
        // arrays.
        ArrayList<byte[]> history = new ArrayList<byte[]>(size);
        for (int i = 0; i < size; i++) {
            WebHistoryItem item = list.getItemAtIndex(i);
            if (null == item) {
                // FIXME: this shouldn't happen
                // need to determine how item got set to null
                Log.w(LOGTAG, "saveState: Unexpected null history item.");
                return null;
            }
            byte[] data = item.getFlattenedData();
            if (data == null) {
                // It would be very odd to not have any data for a given history
                // item. And we will fail to rebuild the history list without
                // flattened data.
                return null;
            }
            history.add(data);
        }
        outState.putSerializable("history", history);
        if (mCertificate != null) {
            outState.putBundle("certificate",
                               SslCertificate.saveState(mCertificate));
        }
        outState.putBoolean("privateBrowsingEnabled", isPrivateBrowsingEnabled());
        mZoomManager.saveZoomState(outState);
        return list;
    }

    /**
     * Save the current display data to the Bundle given. Used in conjunction
     * with {@link #saveState}.
     * @param b A Bundle to store the display data.
     * @param dest The file to store the serialized picture data. Will be
     *             overwritten with this WebView's picture data.
     * @return True if the picture was successfully saved.
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public boolean savePicture(Bundle b, final File dest) {
        checkThread();
        if (dest == null || b == null) {
            return false;
        }
        final Picture p = capturePicture();
        // Use a temporary file while writing to ensure the destination file
        // contains valid data.
        final File temp = new File(dest.getPath() + ".writing");
        new Thread(new Runnable() {
            @Override
            public void run() {
                FileOutputStream out = null;
                try {
                    out = new FileOutputStream(temp);
                    p.writeToStream(out);
                    // Writing the picture succeeded, rename the temporary file
                    // to the destination.
                    temp.renameTo(dest);
                } catch (Exception e) {
                    // too late to do anything about it.
                } finally {
                    if (out != null) {
                        try {
                            out.close();
                        } catch (Exception e) {
                            // Can't do anything about that
                        }
                    }
                    temp.delete();
                }
            }
        }).start();
        // now update the bundle
        b.putInt("scrollX", mScrollX);
        b.putInt("scrollY", mScrollY);
        mZoomManager.saveZoomState(b);
        return true;
    }

    private void restoreHistoryPictureFields(Picture p, Bundle b) {
        int sx = b.getInt("scrollX", 0);
        int sy = b.getInt("scrollY", 0);

        mDrawHistory = true;
        mHistoryPicture = p;

        mScrollX = sx;
        mScrollY = sy;
        mZoomManager.restoreZoomState(b);
        final float scale = mZoomManager.getScale();
        mHistoryWidth = Math.round(p.getWidth() * scale);
        mHistoryHeight = Math.round(p.getHeight() * scale);

        invalidate();
    }

    /**
     * Restore the display data that was save in {@link #savePicture}. Used in
     * conjunction with {@link #restoreState}.
     *
     * Note that this will not work if the WebView is hardware accelerated.
     * @param b A Bundle containing the saved display data.
     * @param src The file where the picture data was stored.
     * @return True if the picture was successfully restored.
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public boolean restorePicture(Bundle b, File src) {
        checkThread();
        if (src == null || b == null) {
            return false;
        }
        if (!src.exists()) {
            return false;
        }
        try {
            final FileInputStream in = new FileInputStream(src);
            final Bundle copy = new Bundle(b);
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        final Picture p = Picture.createFromStream(in);
                        if (p != null) {
                            // Post a runnable on the main thread to update the
                            // history picture fields.
                            mPrivateHandler.post(new Runnable() {
                                @Override
                                public void run() {
                                    restoreHistoryPictureFields(p, copy);
                                }
                            });
                        }
                    } finally {
                        try {
                            in.close();
                        } catch (Exception e) {
                            // Nothing we can do now.
                        }
                    }
                }
            }).start();
        } catch (FileNotFoundException e){
            e.printStackTrace();
        }
        return true;
    }

    /**
     * Saves the view data to the output stream. The output is highly
     * version specific, and may not be able to be loaded by newer versions
     * of WebView.
     * @param stream The {@link OutputStream} to save to
     * @return True if saved successfully
     * @hide
     */
    public boolean saveViewState(OutputStream stream) {
        try {
            return ViewStateSerializer.serializeViewState(stream, this);
        } catch (IOException e) {
            Log.w(LOGTAG, "Failed to saveViewState", e);
        }
        return false;
    }

    /**
     * Loads the view data from the input stream. See
     * {@link #saveViewState(OutputStream)} for more information.
     * @param stream The {@link InputStream} to load from
     * @return True if loaded successfully
     * @hide
     */
    public boolean loadViewState(InputStream stream) {
        try {
            mLoadedPicture = ViewStateSerializer.deserializeViewState(stream, this);
            mBlockWebkitViewMessages = true;
            setNewPicture(mLoadedPicture, true);
            mLoadedPicture.mViewState = null;
            return true;
        } catch (IOException e) {
            Log.w(LOGTAG, "Failed to loadViewState", e);
        }
        return false;
    }

    /**
     * Clears the view state set with {@link #loadViewState(InputStream)}.
     * This WebView will then switch to showing the content from webkit
     * @hide
     */
    public void clearViewState() {
        mBlockWebkitViewMessages = false;
        mLoadedPicture = null;
        invalidate();
    }

    /**
     * Restore the state of this WebView from the given map used in
     * {@link android.app.Activity#onRestoreInstanceState}. This method should
     * be called to restore the state of the WebView before using the object. If
     * it is called after the WebView has had a chance to build state (load
     * pages, create a back/forward list, etc.) there may be undesirable
     * side-effects. Please note that this method no longer restores the
     * display data for this WebView. See {@link #savePicture} and {@link
     * #restorePicture} for saving and restoring the display data.
     * @param inState The incoming Bundle of state.
     * @return The restored back/forward list or null if restoreState failed.
     * @see #savePicture
     * @see #restorePicture
     */
    public WebBackForwardList restoreState(Bundle inState) {
        checkThread();
        WebBackForwardList returnList = null;
        if (inState == null) {
            return returnList;
        }
        if (inState.containsKey("index") && inState.containsKey("history")) {
            mCertificate = SslCertificate.restoreState(
                inState.getBundle("certificate"));

            final WebBackForwardList list = mCallbackProxy.getBackForwardList();
            final int index = inState.getInt("index");
            // We can't use a clone of the list because we need to modify the
            // shared copy, so synchronize instead to prevent concurrent
            // modifications.
            synchronized (list) {
                final List<byte[]> history =
                        (List<byte[]>) inState.getSerializable("history");
                final int size = history.size();
                // Check the index bounds so we don't crash in native code while
                // restoring the history index.
                if (index < 0 || index >= size) {
                    return null;
                }
                for (int i = 0; i < size; i++) {
                    byte[] data = history.remove(0);
                    if (data == null) {
                        // If we somehow have null data, we cannot reconstruct
                        // the item and thus our history list cannot be rebuilt.
                        return null;
                    }
                    WebHistoryItem item = new WebHistoryItem(data);
                    list.addHistoryItem(item);
                }
                // Grab the most recent copy to return to the caller.
                returnList = copyBackForwardList();
                // Update the copy to have the correct index.
                returnList.setCurrentIndex(index);
            }
            // Restore private browsing setting.
            if (inState.getBoolean("privateBrowsingEnabled")) {
                getSettings().setPrivateBrowsingEnabled(true);
            }
            mZoomManager.restoreZoomState(inState);
            // Remove all pending messages because we are restoring previous
            // state.
            mWebViewCore.removeMessages();
            // Send a restore state message.
            mWebViewCore.sendMessage(EventHub.RESTORE_STATE, index);
        }
        return returnList;
    }

    /**
     * Load the given URL with the specified additional HTTP headers.
     * @param url The URL of the resource to load.
     * @param additionalHttpHeaders The additional headers to be used in the
     *            HTTP request for this URL, specified as a map from name to
     *            value. Note that if this map contains any of the headers
     *            that are set by default by the WebView, such as those
     *            controlling caching, accept types or the User-Agent, their
     *            values may be overriden by the WebView's defaults.
     */
    public void loadUrl(String url, Map<String, String> additionalHttpHeaders) {
        checkThread();
        loadUrlImpl(url, additionalHttpHeaders);
    }

    private void loadUrlImpl(String url, Map<String, String> extraHeaders) {
        switchOutDrawHistory();
        WebViewCore.GetUrlData arg = new WebViewCore.GetUrlData();
        arg.mUrl = url;
        arg.mExtraHeaders = extraHeaders;
        mWebViewCore.sendMessage(EventHub.LOAD_URL, arg);
        clearHelpers();
    }

    /**
     * Load the given URL.
     * @param url The URL of the resource to load.
     */
    public void loadUrl(String url) {
        checkThread();
        loadUrlImpl(url);
    }

    private void loadUrlImpl(String url) {
        if (url == null) {
            return;
        }
        loadUrlImpl(url, null);
    }

    /**
     * Load the url with postData using "POST" method into the WebView. If url
     * is not a network url, it will be loaded with {link
     * {@link #loadUrl(String)} instead.
     *
     * @param url The url of the resource to load.
     * @param postData The data will be passed to "POST" request.
     */
    public void postUrl(String url, byte[] postData) {
        checkThread();
        if (URLUtil.isNetworkUrl(url)) {
            switchOutDrawHistory();
            WebViewCore.PostUrlData arg = new WebViewCore.PostUrlData();
            arg.mUrl = url;
            arg.mPostData = postData;
            mWebViewCore.sendMessage(EventHub.POST_URL, arg);
            clearHelpers();
        } else {
            loadUrlImpl(url);
        }
    }

    /**
     * Load the given data into the WebView using a 'data' scheme URL.
     * <p>
     * Note that JavaScript's same origin policy means that script running in a
     * page loaded using this method will be unable to access content loaded
     * using any scheme other than 'data', including 'http(s)'. To avoid this
     * restriction, use {@link
     * #loadDataWithBaseURL(String,String,String,String,String)
     * loadDataWithBaseURL()} with an appropriate base URL.
     * <p>
     * If the value of the encoding parameter is 'base64', then the data must
     * be encoded as base64. Otherwise, the data must use ASCII encoding for
     * octets inside the range of safe URL characters and use the standard %xx
     * hex encoding of URLs for octets outside that range. For example,
     * '#', '%', '\', '?' should be replaced by %23, %25, %27, %3f respectively.
     * <p>
     * The 'data' scheme URL formed by this method uses the default US-ASCII
     * charset. If you need need to set a different charset, you should form a
     * 'data' scheme URL which explicitly specifies a charset parameter in the
     * mediatype portion of the URL and call {@link #loadUrl(String)} instead.
     * Note that the charset obtained from the mediatype portion of a data URL
     * always overrides that specified in the HTML or XML document itself.
     * @param data A String of data in the given encoding.
     * @param mimeType The MIME type of the data, e.g. 'text/html'.
     * @param encoding The encoding of the data.
     */
    public void loadData(String data, String mimeType, String encoding) {
        checkThread();
        loadDataImpl(data, mimeType, encoding);
    }

    private void loadDataImpl(String data, String mimeType, String encoding) {
        StringBuilder dataUrl = new StringBuilder("data:");
        dataUrl.append(mimeType);
        if ("base64".equals(encoding)) {
            dataUrl.append(";base64");
        }
        dataUrl.append(",");
        dataUrl.append(data);
        loadUrlImpl(dataUrl.toString());
    }

    /**
     * Load the given data into the WebView, using baseUrl as the base URL for
     * the content. The base URL is used both to resolve relative URLs and when
     * applying JavaScript's same origin policy. The historyUrl is used for the
     * history entry.
     * <p>
     * Note that content specified in this way can access local device files
     * (via 'file' scheme URLs) only if baseUrl specifies a scheme other than
     * 'http', 'https', 'ftp', 'ftps', 'about' or 'javascript'.
     * <p>
     * If the base URL uses the data scheme, this method is equivalent to
     * calling {@link #loadData(String,String,String) loadData()} and the
     * historyUrl is ignored.
     * @param baseUrl URL to use as the page's base URL. If null defaults to
     *            'about:blank'
     * @param data A String of data in the given encoding.
     * @param mimeType The MIMEType of the data, e.g. 'text/html'. If null,
     *            defaults to 'text/html'.
     * @param encoding The encoding of the data.
     * @param historyUrl URL to use as the history entry, if null defaults to
     *            'about:blank'.
     */
    public void loadDataWithBaseURL(String baseUrl, String data,
            String mimeType, String encoding, String historyUrl) {
        checkThread();

        if (baseUrl != null && baseUrl.toLowerCase().startsWith("data:")) {
            loadDataImpl(data, mimeType, encoding);
            return;
        }
        switchOutDrawHistory();
        WebViewCore.BaseUrlData arg = new WebViewCore.BaseUrlData();
        arg.mBaseUrl = baseUrl;
        arg.mData = data;
        arg.mMimeType = mimeType;
        arg.mEncoding = encoding;
        arg.mHistoryUrl = historyUrl;
        mWebViewCore.sendMessage(EventHub.LOAD_DATA, arg);
        clearHelpers();
    }

    /**
     * Saves the current view as a web archive.
     *
     * @param filename The filename where the archive should be placed.
     */
    public void saveWebArchive(String filename) {
        checkThread();
        saveWebArchiveImpl(filename, false, null);
    }

    /* package */ static class SaveWebArchiveMessage {
        SaveWebArchiveMessage (String basename, boolean autoname, ValueCallback<String> callback) {
            mBasename = basename;
            mAutoname = autoname;
            mCallback = callback;
        }

        /* package */ final String mBasename;
        /* package */ final boolean mAutoname;
        /* package */ final ValueCallback<String> mCallback;
        /* package */ String mResultFile;
    }

    /**
     * Saves the current view as a web archive.
     *
     * @param basename The filename where the archive should be placed.
     * @param autoname If false, takes basename to be a file. If true, basename
     *                 is assumed to be a directory in which a filename will be
     *                 chosen according to the url of the current page.
     * @param callback Called after the web archive has been saved. The
     *                 parameter for onReceiveValue will either be the filename
     *                 under which the file was saved, or null if saving the
     *                 file failed.
     */
    public void saveWebArchive(String basename, boolean autoname, ValueCallback<String> callback) {
        checkThread();
        saveWebArchiveImpl(basename, autoname, callback);
    }

    private void saveWebArchiveImpl(String basename, boolean autoname,
            ValueCallback<String> callback) {
        mWebViewCore.sendMessage(EventHub.SAVE_WEBARCHIVE,
            new SaveWebArchiveMessage(basename, autoname, callback));
    }

    /**
     * Stop the current load.
     */
    public void stopLoading() {
        checkThread();
        // TODO: should we clear all the messages in the queue before sending
        // STOP_LOADING?
        switchOutDrawHistory();
        mWebViewCore.sendMessage(EventHub.STOP_LOADING);
    }

    /**
     * Reload the current url.
     */
    public void reload() {
        checkThread();
        clearHelpers();
        switchOutDrawHistory();
        mWebViewCore.sendMessage(EventHub.RELOAD);
    }

    /**
     * Return true if this WebView has a back history item.
     * @return True iff this WebView has a back history item.
     */
    public boolean canGoBack() {
        checkThread();
        WebBackForwardList l = mCallbackProxy.getBackForwardList();
        synchronized (l) {
            if (l.getClearPending()) {
                return false;
            } else {
                return l.getCurrentIndex() > 0;
            }
        }
    }

    /**
     * Go back in the history of this WebView.
     */
    public void goBack() {
        checkThread();
        goBackOrForwardImpl(-1);
    }

    /**
     * Return true if this WebView has a forward history item.
     * @return True iff this Webview has a forward history item.
     */
    public boolean canGoForward() {
        checkThread();
        WebBackForwardList l = mCallbackProxy.getBackForwardList();
        synchronized (l) {
            if (l.getClearPending()) {
                return false;
            } else {
                return l.getCurrentIndex() < l.getSize() - 1;
            }
        }
    }

    /**
     * Go forward in the history of this WebView.
     */
    public void goForward() {
        checkThread();
        goBackOrForwardImpl(1);
    }

    /**
     * Return true if the page can go back or forward the given
     * number of steps.
     * @param steps The negative or positive number of steps to move the
     *              history.
     */
    public boolean canGoBackOrForward(int steps) {
        checkThread();
        WebBackForwardList l = mCallbackProxy.getBackForwardList();
        synchronized (l) {
            if (l.getClearPending()) {
                return false;
            } else {
                int newIndex = l.getCurrentIndex() + steps;
                return newIndex >= 0 && newIndex < l.getSize();
            }
        }
    }

    /**
     * Go to the history item that is the number of steps away from
     * the current item. Steps is negative if backward and positive
     * if forward.
     * @param steps The number of steps to take back or forward in the back
     *              forward list.
     */
    public void goBackOrForward(int steps) {
        checkThread();
        goBackOrForwardImpl(steps);
    }

    private void goBackOrForwardImpl(int steps) {
        goBackOrForward(steps, false);
    }

    private void goBackOrForward(int steps, boolean ignoreSnapshot) {
        if (steps != 0) {
            clearHelpers();
            mWebViewCore.sendMessage(EventHub.GO_BACK_FORWARD, steps,
                    ignoreSnapshot ? 1 : 0);
        }
    }

    /**
     * Returns true if private browsing is enabled in this WebView.
     */
    public boolean isPrivateBrowsingEnabled() {
        checkThread();
        return getSettings().isPrivateBrowsingEnabled();
    }

    private void startPrivateBrowsing() {
        getSettings().setPrivateBrowsingEnabled(true);
    }

    private boolean extendScroll(int y) {
        int finalY = mScroller.getFinalY();
        int newY = pinLocY(finalY + y);
        if (newY == finalY) return false;
        mScroller.setFinalY(newY);
        mScroller.extendDuration(computeDuration(0, y));
        return true;
    }

    /**
     * Scroll the contents of the view up by half the view size
     * @param top true to jump to the top of the page
     * @return true if the page was scrolled
     */
    public boolean pageUp(boolean top) {
        checkThread();
        if (mNativeClass == 0) {
            return false;
        }
        nativeClearCursor(); // start next trackball movement from page edge
        if (top) {
            // go to the top of the document
            return pinScrollTo(mScrollX, 0, true, 0);
        }
        // Page up
        int h = getHeight();
        int y;
        if (h > 2 * PAGE_SCROLL_OVERLAP) {
            y = -h + PAGE_SCROLL_OVERLAP;
        } else {
            y = -h / 2;
        }
        return mScroller.isFinished() ? pinScrollBy(0, y, true, 0)
                : extendScroll(y);
    }

    /**
     * Scroll the contents of the view down by half the page size
     * @param bottom true to jump to bottom of page
     * @return true if the page was scrolled
     */
    public boolean pageDown(boolean bottom) {
        checkThread();
        if (mNativeClass == 0) {
            return false;
        }
        nativeClearCursor(); // start next trackball movement from page edge
        if (bottom) {
            return pinScrollTo(mScrollX, computeRealVerticalScrollRange(), true, 0);
        }
        // Page down.
        int h = getHeight();
        int y;
        if (h > 2 * PAGE_SCROLL_OVERLAP) {
            y = h - PAGE_SCROLL_OVERLAP;
        } else {
            y = h / 2;
        }
        return mScroller.isFinished() ? pinScrollBy(0, y, true, 0)
                : extendScroll(y);
    }

    /**
     * Clear the view so that onDraw() will draw nothing but white background,
     * and onMeasure() will return 0 if MeasureSpec is not MeasureSpec.EXACTLY
     */
    public void clearView() {
        checkThread();
        mContentWidth = 0;
        mContentHeight = 0;
        setBaseLayer(0, null, false, false);
        mWebViewCore.sendMessage(EventHub.CLEAR_CONTENT);
    }

    /**
     * Return a new picture that captures the current display of the webview.
     * This is a copy of the display, and will be unaffected if the webview
     * later loads a different URL.
     *
     * @return a picture containing the current contents of the view. Note this
     *         picture is of the entire document, and is not restricted to the
     *         bounds of the view.
     */
    public Picture capturePicture() {
        checkThread();
        if (mNativeClass == 0) return null;
        Picture result = new Picture();
        nativeCopyBaseContentToPicture(result);
        return result;
    }

    /**
     *  Return true if the browser is displaying a TextView for text input.
     */
    private boolean inEditingMode() {
        return mWebTextView != null && mWebTextView.getParent() != null;
    }

    /**
     * Remove the WebTextView.
     */
    private void clearTextEntry() {
        if (inEditingMode()) {
            mWebTextView.remove();
        } else {
            // The keyboard may be open with the WebView as the served view
            hideSoftKeyboard();
        }
    }

    /**
     * Return the current scale of the WebView
     * @return The current scale.
     */
    public float getScale() {
        checkThread();
        return mZoomManager.getScale();
    }

    /**
     * Compute the reading level scale of the WebView
     * @param scale The current scale.
     * @return The reading level scale.
     */
    /*package*/ float computeReadingLevelScale(float scale) {
        return mZoomManager.computeReadingLevelScale(scale);
    }

    /**
     * Set the initial scale for the WebView. 0 means default. If
     * {@link WebSettings#getUseWideViewPort()} is true, it zooms out all the
     * way. Otherwise it starts with 100%. If initial scale is greater than 0,
     * WebView starts with this value as initial scale.
     * Please note that unlike the scale properties in the viewport meta tag,
     * this method doesn't take the screen density into account.
     *
     * @param scaleInPercent The initial scale in percent.
     */
    public void setInitialScale(int scaleInPercent) {
        checkThread();
        mZoomManager.setInitialScaleInPercent(scaleInPercent);
    }

    /**
     * Invoke the graphical zoom picker widget for this WebView. This will
     * result in the zoom widget appearing on the screen to control the zoom
     * level of this WebView.
     */
    public void invokeZoomPicker() {
        checkThread();
        if (!getSettings().supportZoom()) {
            Log.w(LOGTAG, "This WebView doesn't support zoom.");
            return;
        }
        clearHelpers();
        mZoomManager.invokeZoomPicker();
    }

    /**
     * Return a HitTestResult based on the current cursor node. If a HTML::a tag
     * is found and the anchor has a non-JavaScript url, the HitTestResult type
     * is set to SRC_ANCHOR_TYPE and the url is set in the "extra" field. If the
     * anchor does not have a url or if it is a JavaScript url, the type will
     * be UNKNOWN_TYPE and the url has to be retrieved through
     * {@link #requestFocusNodeHref} asynchronously. If a HTML::img tag is
     * found, the HitTestResult type is set to IMAGE_TYPE and the url is set in
     * the "extra" field. A type of
     * SRC_IMAGE_ANCHOR_TYPE indicates an anchor with a url that has an image as
     * a child node. If a phone number is found, the HitTestResult type is set
     * to PHONE_TYPE and the phone number is set in the "extra" field of
     * HitTestResult. If a map address is found, the HitTestResult type is set
     * to GEO_TYPE and the address is set in the "extra" field of HitTestResult.
     * If an email address is found, the HitTestResult type is set to EMAIL_TYPE
     * and the email is set in the "extra" field of HitTestResult. Otherwise,
     * HitTestResult type is set to UNKNOWN_TYPE.
     */
    public HitTestResult getHitTestResult() {
        checkThread();
        return hitTestResult(mInitialHitTestResult);
    }

    private HitTestResult hitTestResult(HitTestResult fallback) {
        if (mNativeClass == 0 || sDisableNavcache) {
            return fallback;
        }

        HitTestResult result = new HitTestResult();
        if (nativeHasCursorNode()) {
            if (nativeCursorIsTextInput()) {
                result.setType(HitTestResult.EDIT_TEXT_TYPE);
            } else {
                String text = nativeCursorText();
                if (text != null) {
                    if (text.startsWith(SCHEME_TEL)) {
                        result.setType(HitTestResult.PHONE_TYPE);
                        result.setExtra(URLDecoder.decode(text
                                .substring(SCHEME_TEL.length())));
                    } else if (text.startsWith(SCHEME_MAILTO)) {
                        result.setType(HitTestResult.EMAIL_TYPE);
                        result.setExtra(text.substring(SCHEME_MAILTO.length()));
                    } else if (text.startsWith(SCHEME_GEO)) {
                        result.setType(HitTestResult.GEO_TYPE);
                        result.setExtra(URLDecoder.decode(text
                                .substring(SCHEME_GEO.length())));
                    } else if (nativeCursorIsAnchor()) {
                        result.setType(HitTestResult.SRC_ANCHOR_TYPE);
                        result.setExtra(text);
                    }
                }
            }
        } else if (fallback != null) {
            /* If webkit causes a rebuild while the long press is in progress,
             * the cursor node may be reset, even if it is still around. This
             * uses the cursor node saved when the touch began. Since the
             * nativeImageURI below only changes the result if it is successful,
             * this uses the data beneath the touch if available or the original
             * tap data otherwise.
             */
            Log.v(LOGTAG, "hitTestResult use fallback");
            result = fallback;
        }
        int type = result.getType();
        if (type == HitTestResult.UNKNOWN_TYPE
                || type == HitTestResult.SRC_ANCHOR_TYPE) {
            // Now check to see if it is an image.
            int contentX = viewToContentX(mLastTouchX + mScrollX);
            int contentY = viewToContentY(mLastTouchY + mScrollY);
            String text = nativeImageURI(contentX, contentY);
            if (text != null) {
                result.setType(type == HitTestResult.UNKNOWN_TYPE ?
                        HitTestResult.IMAGE_TYPE :
                        HitTestResult.SRC_IMAGE_ANCHOR_TYPE);
                result.setExtra(text);
            }
        }
        return result;
    }

    int getBlockLeftEdge(int x, int y, float readingScale) {
        if (!sDisableNavcache) {
            return nativeGetBlockLeftEdge(x, y, readingScale);
        }

        float invReadingScale = 1.0f / readingScale;
        int readingWidth = (int) (getViewWidth() * invReadingScale);
        int left = NO_LEFTEDGE;
        if (mFocusedNode != null) {
            final int length = mFocusedNode.mEnclosingParentRects.length;
            for (int i = 0; i < length; i++) {
                Rect rect = mFocusedNode.mEnclosingParentRects[i];
                if (rect.width() < mFocusedNode.mHitTestSlop) {
                    // ignore bounding boxes that are too small
                    continue;
                } else if (left != NO_LEFTEDGE && rect.width() > readingWidth) {
                    // stop when bounding box doesn't fit the screen width
                    // at reading scale
                    break;
                }

                left = rect.left;
            }
        }

        return left;
    }

    // Called by JNI when the DOM has changed the focus.  Clear the focus so
    // that new keys will go to the newly focused field
    private void domChangedFocus() {
        if (inEditingMode()) {
            mPrivateHandler.obtainMessage(DOM_FOCUS_CHANGED).sendToTarget();
        }
    }
    /**
     * Request the anchor or image element URL at the last tapped point.
     * If hrefMsg is null, this method returns immediately and does not
     * dispatch hrefMsg to its target. If the tapped point hits an image,
     * an anchor, or an image in an anchor, the message associates
     * strings in named keys in its data. The value paired with the key
     * may be an empty string.
     *
     * @param hrefMsg This message will be dispatched with the result of the
     *                request. The message data contains three keys:
     *                - "url" returns the anchor's href attribute.
     *                - "title" returns the anchor's text.
     *                - "src" returns the image's src attribute.
     */
    public void requestFocusNodeHref(Message hrefMsg) {
        checkThread();
        if (hrefMsg == null) {
            return;
        }
        int contentX = viewToContentX(mLastTouchX + mScrollX);
        int contentY = viewToContentY(mLastTouchY + mScrollY);
        if (mFocusedNode != null && mFocusedNode.mHitTestX == contentX
                && mFocusedNode.mHitTestY == contentY) {
            hrefMsg.getData().putString(FocusNodeHref.URL, mFocusedNode.mLinkUrl);
            hrefMsg.getData().putString(FocusNodeHref.TITLE, mFocusedNode.mAnchorText);
            hrefMsg.getData().putString(FocusNodeHref.SRC, mFocusedNode.mImageUrl);
            hrefMsg.sendToTarget();
            return;
        }
        if (nativeHasCursorNode()) {
            Rect cursorBounds = nativeGetCursorRingBounds();
            if (!cursorBounds.contains(contentX, contentY)) {
                int slop = viewToContentDimension(mNavSlop);
                cursorBounds.inset(-slop, -slop);
                if (cursorBounds.contains(contentX, contentY)) {
                    contentX = cursorBounds.centerX();
                    contentY = cursorBounds.centerY();
                }
            }
        }
        mWebViewCore.sendMessage(EventHub.REQUEST_CURSOR_HREF,
                contentX, contentY, hrefMsg);
    }

    /**
     * Request the url of the image last touched by the user. msg will be sent
     * to its target with a String representing the url as its object.
     *
     * @param msg This message will be dispatched with the result of the request
     *            as the data member with "url" as key. The result can be null.
     */
    public void requestImageRef(Message msg) {
        checkThread();
        if (0 == mNativeClass) return; // client isn't initialized
        int contentX = viewToContentX(mLastTouchX + mScrollX);
        int contentY = viewToContentY(mLastTouchY + mScrollY);
        String ref = nativeImageURI(contentX, contentY);
        Bundle data = msg.getData();
        data.putString("url", ref);
        msg.setData(data);
        msg.sendToTarget();
    }

    static int pinLoc(int x, int viewMax, int docMax) {
//        Log.d(LOGTAG, "-- pinLoc " + x + " " + viewMax + " " + docMax);
        if (docMax < viewMax) {   // the doc has room on the sides for "blank"
            // pin the short document to the top/left of the screen
            x = 0;
//            Log.d(LOGTAG, "--- center " + x);
        } else if (x < 0) {
            x = 0;
//            Log.d(LOGTAG, "--- zero");
        } else if (x + viewMax > docMax) {
            x = docMax - viewMax;
//            Log.d(LOGTAG, "--- pin " + x);
        }
        return x;
    }

    // Expects x in view coordinates
    int pinLocX(int x) {
        if (mInOverScrollMode) return x;
        return pinLoc(x, getViewWidth(), computeRealHorizontalScrollRange());
    }

    // Expects y in view coordinates
    int pinLocY(int y) {
        if (mInOverScrollMode) return y;
        return pinLoc(y, getViewHeightWithTitle(),
                      computeRealVerticalScrollRange() + getTitleHeight());
    }

    /**
     * A title bar which is embedded in this WebView, and scrolls along with it
     * vertically, but not horizontally.
     */
    private View mTitleBar;

    /**
     * the title bar rendering gravity
     */
    private int mTitleGravity;

    /**
     * Add or remove a title bar to be embedded into the WebView, and scroll
     * along with it vertically, while remaining in view horizontally. Pass
     * null to remove the title bar from the WebView, and return to drawing
     * the WebView normally without translating to account for the title bar.
     * @hide
     */
    public void setEmbeddedTitleBar(View v) {
        if (mTitleBar == v) return;
        if (mTitleBar != null) {
            removeView(mTitleBar);
        }
        if (null != v) {
            addView(v, new AbsoluteLayout.LayoutParams(
                    ViewGroup.LayoutParams.MATCH_PARENT,
                    ViewGroup.LayoutParams.WRAP_CONTENT, 0, 0));
        }
        mTitleBar = v;
    }

    /**
     * Set where to render the embedded title bar
     * NO_GRAVITY at the top of the page
     * TOP        at the top of the screen
     * @hide
     */
    public void setTitleBarGravity(int gravity) {
        mTitleGravity = gravity;
        // force refresh
        invalidate();
    }

    /**
     * Given a distance in view space, convert it to content space. Note: this
     * does not reflect translation, just scaling, so this should not be called
     * with coordinates, but should be called for dimensions like width or
     * height.
     */
    private int viewToContentDimension(int d) {
        return Math.round(d * mZoomManager.getInvScale());
    }

    /**
     * Given an x coordinate in view space, convert it to content space.  Also
     * may be used for absolute heights (such as for the WebTextView's
     * textSize, which is unaffected by the height of the title bar).
     */
    /*package*/ int viewToContentX(int x) {
        return viewToContentDimension(x);
    }

    /**
     * Given a y coordinate in view space, convert it to content space.
     * Takes into account the height of the title bar if there is one
     * embedded into the WebView.
     */
    /*package*/ int viewToContentY(int y) {
        return viewToContentDimension(y - getTitleHeight());
    }

    /**
     * Given a x coordinate in view space, convert it to content space.
     * Returns the result as a float.
     */
    private float viewToContentXf(int x) {
        return x * mZoomManager.getInvScale();
    }

    /**
     * Given a y coordinate in view space, convert it to content space.
     * Takes into account the height of the title bar if there is one
     * embedded into the WebView. Returns the result as a float.
     */
    private float viewToContentYf(int y) {
        return (y - getTitleHeight()) * mZoomManager.getInvScale();
    }

    /**
     * Given a distance in content space, convert it to view space. Note: this
     * does not reflect translation, just scaling, so this should not be called
     * with coordinates, but should be called for dimensions like width or
     * height.
     */
    /*package*/ int contentToViewDimension(int d) {
        return Math.round(d * mZoomManager.getScale());
    }

    /**
     * Given an x coordinate in content space, convert it to view
     * space.
     */
    /*package*/ int contentToViewX(int x) {
        return contentToViewDimension(x);
    }

    /**
     * Given a y coordinate in content space, convert it to view
     * space.  Takes into account the height of the title bar.
     */
    /*package*/ int contentToViewY(int y) {
        return contentToViewDimension(y) + getTitleHeight();
    }

    private Rect contentToViewRect(Rect x) {
        return new Rect(contentToViewX(x.left), contentToViewY(x.top),
                        contentToViewX(x.right), contentToViewY(x.bottom));
    }

    /*  To invalidate a rectangle in content coordinates, we need to transform
        the rect into view coordinates, so we can then call invalidate(...).

        Normally, we would just call contentToView[XY](...), which eventually
        calls Math.round(coordinate * mActualScale). However, for invalidates,
        we need to account for the slop that occurs with antialiasing. To
        address that, we are a little more liberal in the size of the rect that
        we invalidate.

        This liberal calculation calls floor() for the top/left, and ceil() for
        the bottom/right coordinates. This catches the possible extra pixels of
        antialiasing that we might have missed with just round().
     */

    // Called by JNI to invalidate the View, given rectangle coordinates in
    // content space
    private void viewInvalidate(int l, int t, int r, int b) {
        final float scale = mZoomManager.getScale();
        final int dy = getTitleHeight();
        invalidate((int)Math.floor(l * scale),
                   (int)Math.floor(t * scale) + dy,
                   (int)Math.ceil(r * scale),
                   (int)Math.ceil(b * scale) + dy);
    }

    // Called by JNI to invalidate the View after a delay, given rectangle
    // coordinates in content space
    private void viewInvalidateDelayed(long delay, int l, int t, int r, int b) {
        final float scale = mZoomManager.getScale();
        final int dy = getTitleHeight();
        postInvalidateDelayed(delay,
                              (int)Math.floor(l * scale),
                              (int)Math.floor(t * scale) + dy,
                              (int)Math.ceil(r * scale),
                              (int)Math.ceil(b * scale) + dy);
    }

    private void invalidateContentRect(Rect r) {
        viewInvalidate(r.left, r.top, r.right, r.bottom);
    }

    // stop the scroll animation, and don't let a subsequent fling add
    // to the existing velocity
    private void abortAnimation() {
        mScroller.abortAnimation();
        mLastVelocity = 0;
    }

    /* call from webcoreview.draw(), so we're still executing in the UI thread
    */
    private void recordNewContentSize(int w, int h, boolean updateLayout) {

        // premature data from webkit, ignore
        if ((w | h) == 0) {
            return;
        }

        // don't abort a scroll animation if we didn't change anything
        if (mContentWidth != w || mContentHeight != h) {
            // record new dimensions
            mContentWidth = w;
            mContentHeight = h;
            // If history Picture is drawn, don't update scroll. They will be
            // updated when we get out of that mode.
            if (!mDrawHistory) {
                // repin our scroll, taking into account the new content size
                updateScrollCoordinates(pinLocX(mScrollX), pinLocY(mScrollY));
                if (!mScroller.isFinished()) {
                    // We are in the middle of a scroll.  Repin the final scroll
                    // position.
                    mScroller.setFinalX(pinLocX(mScroller.getFinalX()));
                    mScroller.setFinalY(pinLocY(mScroller.getFinalY()));
                }
            }
        }
        contentSizeChanged(updateLayout);
    }

    // Used to avoid sending many visible rect messages.
    private Rect mLastVisibleRectSent = new Rect();
    private Rect mLastGlobalRect = new Rect();
    private Rect mVisibleRect = new Rect();
    private Rect mGlobalVisibleRect = new Rect();
    private Point mScrollOffset = new Point();

    Rect sendOurVisibleRect() {
        if (mZoomManager.isPreventingWebkitUpdates()) return mLastVisibleRectSent;
        calcOurContentVisibleRect(mVisibleRect);
        // Rect.equals() checks for null input.
        if (!mVisibleRect.equals(mLastVisibleRectSent)) {
            if (!mBlockWebkitViewMessages) {
                mScrollOffset.set(mVisibleRect.left, mVisibleRect.top);
                mWebViewCore.removeMessages(EventHub.SET_SCROLL_OFFSET);
                mWebViewCore.sendMessage(EventHub.SET_SCROLL_OFFSET,
                        nativeMoveGeneration(), mSendScrollEvent ? 1 : 0, mScrollOffset);
            }
            mLastVisibleRectSent.set(mVisibleRect);
            mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);
        }
        if (getGlobalVisibleRect(mGlobalVisibleRect)
                && !mGlobalVisibleRect.equals(mLastGlobalRect)) {
            if (DebugFlags.WEB_VIEW) {
                Log.v(LOGTAG, "sendOurVisibleRect=(" + mGlobalVisibleRect.left + ","
                        + mGlobalVisibleRect.top + ",r=" + mGlobalVisibleRect.right + ",b="
                        + mGlobalVisibleRect.bottom);
            }
            // TODO: the global offset is only used by windowRect()
            // in ChromeClientAndroid ; other clients such as touch
            // and mouse events could return view + screen relative points.
            if (!mBlockWebkitViewMessages) {
                mWebViewCore.sendMessage(EventHub.SET_GLOBAL_BOUNDS, mGlobalVisibleRect);
            }
            mLastGlobalRect.set(mGlobalVisibleRect);
        }
        return mVisibleRect;
    }

    private Point mGlobalVisibleOffset = new Point();
    // Sets r to be the visible rectangle of our webview in view coordinates
    private void calcOurVisibleRect(Rect r) {
        getGlobalVisibleRect(r, mGlobalVisibleOffset);
        r.offset(-mGlobalVisibleOffset.x, -mGlobalVisibleOffset.y);
    }

    // Sets r to be our visible rectangle in content coordinates
    private void calcOurContentVisibleRect(Rect r) {
        calcOurVisibleRect(r);
        r.left = viewToContentX(r.left);
        // viewToContentY will remove the total height of the title bar.  Add
        // the visible height back in to account for the fact that if the title
        // bar is partially visible, the part of the visible rect which is
        // displaying our content is displaced by that amount.
        r.top = viewToContentY(r.top + getVisibleTitleHeightImpl());
        r.right = viewToContentX(r.right);
        r.bottom = viewToContentY(r.bottom);
    }

    private Rect mContentVisibleRect = new Rect();
    // Sets r to be our visible rectangle in content coordinates. We use this
    // method on the native side to compute the position of the fixed layers.
    // Uses floating coordinates (necessary to correctly place elements when
    // the scale factor is not 1)
    private void calcOurContentVisibleRectF(RectF r) {
        calcOurVisibleRect(mContentVisibleRect);
        r.left = viewToContentXf(mContentVisibleRect.left);
        // viewToContentY will remove the total height of the title bar.  Add
        // the visible height back in to account for the fact that if the title
        // bar is partially visible, the part of the visible rect which is
        // displaying our content is displaced by that amount.
        r.top = viewToContentYf(mContentVisibleRect.top + getVisibleTitleHeightImpl());
        r.right = viewToContentXf(mContentVisibleRect.right);
        r.bottom = viewToContentYf(mContentVisibleRect.bottom);
    }

    static class ViewSizeData {
        int mWidth;
        int mHeight;
        float mHeightWidthRatio;
        int mActualViewHeight;
        int mTextWrapWidth;
        int mAnchorX;
        int mAnchorY;
        float mScale;
        boolean mIgnoreHeight;
    }

    /**
     * Compute unzoomed width and height, and if they differ from the last
     * values we sent, send them to webkit (to be used as new viewport)
     *
     * @param force ensures that the message is sent to webkit even if the width
     * or height has not changed since the last message
     *
     * @return true if new values were sent
     */
    boolean sendViewSizeZoom(boolean force) {
        if (mBlockWebkitViewMessages) return false;
        if (mZoomManager.isPreventingWebkitUpdates()) return false;

        int viewWidth = getViewWidth();
        int newWidth = Math.round(viewWidth * mZoomManager.getInvScale());
        // This height could be fixed and be different from actual visible height.
        int viewHeight = getViewHeightWithTitle() - getTitleHeight();
        int newHeight = Math.round(viewHeight * mZoomManager.getInvScale());
        // Make the ratio more accurate than (newHeight / newWidth), since the
        // latter both are calculated and rounded.
        float heightWidthRatio = (float) viewHeight / viewWidth;
        /*
         * Because the native side may have already done a layout before the
         * View system was able to measure us, we have to send a height of 0 to
         * remove excess whitespace when we grow our width. This will trigger a
         * layout and a change in content size. This content size change will
         * mean that contentSizeChanged will either call this method directly or
         * indirectly from onSizeChanged.
         */
        if (newWidth > mLastWidthSent && mWrapContent) {
            newHeight = 0;
            heightWidthRatio = 0;
        }
        // Actual visible content height.
        int actualViewHeight = Math.round(getViewHeight() * mZoomManager.getInvScale());
        // Avoid sending another message if the dimensions have not changed.
        if (newWidth != mLastWidthSent || newHeight != mLastHeightSent || force ||
                actualViewHeight != mLastActualHeightSent) {
            ViewSizeData data = new ViewSizeData();
            data.mWidth = newWidth;
            data.mHeight = newHeight;
            data.mHeightWidthRatio = heightWidthRatio;
            data.mActualViewHeight = actualViewHeight;
            data.mTextWrapWidth = Math.round(viewWidth / mZoomManager.getTextWrapScale());
            data.mScale = mZoomManager.getScale();
            data.mIgnoreHeight = mZoomManager.isFixedLengthAnimationInProgress()
                    && !mHeightCanMeasure;
            data.mAnchorX = mZoomManager.getDocumentAnchorX();
            data.mAnchorY = mZoomManager.getDocumentAnchorY();
            mWebViewCore.sendMessage(EventHub.VIEW_SIZE_CHANGED, data);
            mLastWidthSent = newWidth;
            mLastHeightSent = newHeight;
            mLastActualHeightSent = actualViewHeight;
            mZoomManager.clearDocumentAnchor();
            return true;
        }
        return false;
    }

    /**
     * Update the double-tap zoom.
     */
    /* package */ void updateDoubleTapZoom(int doubleTapZoom) {
        mZoomManager.updateDoubleTapZoom(doubleTapZoom);
    }

    private int computeRealHorizontalScrollRange() {
        if (mDrawHistory) {
            return mHistoryWidth;
        } else {
            // to avoid rounding error caused unnecessary scrollbar, use floor
            return (int) Math.floor(mContentWidth * mZoomManager.getScale());
        }
    }

    @Override
    protected int computeHorizontalScrollRange() {
        int range = computeRealHorizontalScrollRange();

        // Adjust reported range if overscrolled to compress the scroll bars
        final int scrollX = mScrollX;
        final int overscrollRight = computeMaxScrollX();
        if (scrollX < 0) {
            range -= scrollX;
        } else if (scrollX > overscrollRight) {
            range += scrollX - overscrollRight;
        }

        return range;
    }

    @Override
    protected int computeHorizontalScrollOffset() {
        return Math.max(mScrollX, 0);
    }

    private int computeRealVerticalScrollRange() {
        if (mDrawHistory) {
            return mHistoryHeight;
        } else {
            // to avoid rounding error caused unnecessary scrollbar, use floor
            return (int) Math.floor(mContentHeight * mZoomManager.getScale());
        }
    }

    @Override
    protected int computeVerticalScrollRange() {
        int range = computeRealVerticalScrollRange();

        // Adjust reported range if overscrolled to compress the scroll bars
        final int scrollY = mScrollY;
        final int overscrollBottom = computeMaxScrollY();
        if (scrollY < 0) {
            range -= scrollY;
        } else if (scrollY > overscrollBottom) {
            range += scrollY - overscrollBottom;
        }

        return range;
    }

    @Override
    protected int computeVerticalScrollOffset() {
        return Math.max(mScrollY - getTitleHeight(), 0);
    }

    @Override
    protected int computeVerticalScrollExtent() {
        return getViewHeight();
    }

    /** @hide */
    @Override
    protected void onDrawVerticalScrollBar(Canvas canvas,
                                           Drawable scrollBar,
                                           int l, int t, int r, int b) {
        if (mScrollY < 0) {
            t -= mScrollY;
        }
        scrollBar.setBounds(l, t + getVisibleTitleHeightImpl(), r, b);
        scrollBar.draw(canvas);
    }

    @Override
    protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX,
            boolean clampedY) {
        // Special-case layer scrolling so that we do not trigger normal scroll
        // updating.
        if (mTouchMode == TOUCH_DRAG_LAYER_MODE) {
            scrollLayerTo(scrollX, scrollY);
            return;
        }
        mInOverScrollMode = false;
        int maxX = computeMaxScrollX();
        int maxY = computeMaxScrollY();
        if (maxX == 0) {
            // do not over scroll x if the page just fits the screen
            scrollX = pinLocX(scrollX);
        } else if (scrollX < 0 || scrollX > maxX) {
            mInOverScrollMode = true;
        }
        if (scrollY < 0 || scrollY > maxY) {
            mInOverScrollMode = true;
        }

        int oldX = mScrollX;
        int oldY = mScrollY;

        super.scrollTo(scrollX, scrollY);

        if (mOverScrollGlow != null) {
            mOverScrollGlow.pullGlow(mScrollX, mScrollY, oldX, oldY, maxX, maxY);
        }
    }

    /**
     * Get the url for the current page. This is not always the same as the url
     * passed to WebViewClient.onPageStarted because although the load for
     * that url has begun, the current page may not have changed.
     * @return The url for the current page.
     */
    public String getUrl() {
        checkThread();
        WebHistoryItem h = mCallbackProxy.getBackForwardList().getCurrentItem();
        return h != null ? h.getUrl() : null;
    }

    /**
     * Get the original url for the current page. This is not always the same
     * as the url passed to WebViewClient.onPageStarted because although the
     * load for that url has begun, the current page may not have changed.
     * Also, there may have been redirects resulting in a different url to that
     * originally requested.
     * @return The url that was originally requested for the current page.
     */
    public String getOriginalUrl() {
        checkThread();
        WebHistoryItem h = mCallbackProxy.getBackForwardList().getCurrentItem();
        return h != null ? h.getOriginalUrl() : null;
    }

    /**
     * Get the title for the current page. This is the title of the current page
     * until WebViewClient.onReceivedTitle is called.
     * @return The title for the current page.
     */
    public String getTitle() {
        checkThread();
        WebHistoryItem h = mCallbackProxy.getBackForwardList().getCurrentItem();
        return h != null ? h.getTitle() : null;
    }

    /**
     * Get the favicon for the current page. This is the favicon of the current
     * page until WebViewClient.onReceivedIcon is called.
     * @return The favicon for the current page.
     */
    public Bitmap getFavicon() {
        checkThread();
        WebHistoryItem h = mCallbackProxy.getBackForwardList().getCurrentItem();
        return h != null ? h.getFavicon() : null;
    }

    /**
     * Get the touch icon url for the apple-touch-icon <link> element, or
     * a URL on this site's server pointing to the standard location of a
     * touch icon.
     * @hide
     */
    public String getTouchIconUrl() {
        WebHistoryItem h = mCallbackProxy.getBackForwardList().getCurrentItem();
        return h != null ? h.getTouchIconUrl() : null;
    }

    /**
     * Get the progress for the current page.
     * @return The progress for the current page between 0 and 100.
     */
    public int getProgress() {
        checkThread();
        return mCallbackProxy.getProgress();
    }

    /**
     * @return the height of the HTML content.
     */
    public int getContentHeight() {
        checkThread();
        return mContentHeight;
    }

    /**
     * @return the width of the HTML content.
     * @hide
     */
    public int getContentWidth() {
        return mContentWidth;
    }

    /**
     * @hide
     */
    public int getPageBackgroundColor() {
        return nativeGetBackgroundColor();
    }

    /**
     * Pause all layout, parsing, and JavaScript timers for all webviews. This
     * is a global requests, not restricted to just this webview. This can be
     * useful if the application has been paused.
     */
    public void pauseTimers() {
        checkThread();
        mWebViewCore.sendMessage(EventHub.PAUSE_TIMERS);
    }

    /**
     * Resume all layout, parsing, and JavaScript timers for all webviews.
     * This will resume dispatching all timers.
     */
    public void resumeTimers() {
        checkThread();
        mWebViewCore.sendMessage(EventHub.RESUME_TIMERS);
    }

    /**
     * Call this to pause any extra processing associated with this WebView and
     * its associated DOM, plugins, JavaScript etc. For example, if the WebView
     * is taken offscreen, this could be called to reduce unnecessary CPU or
     * network traffic. When the WebView is again "active", call onResume().
     *
     * Note that this differs from pauseTimers(), which affects all WebViews.
     */
    public void onPause() {
        checkThread();
        if (!mIsPaused) {
            mIsPaused = true;
            mWebViewCore.sendMessage(EventHub.ON_PAUSE);
            // We want to pause the current playing video when switching out
            // from the current WebView/tab.
            if (mHTML5VideoViewProxy != null) {
                mHTML5VideoViewProxy.pauseAndDispatch();
            }
            if (mNativeClass != 0) {
                nativeSetPauseDrawing(mNativeClass, true);
            }

            cancelSelectDialog();
            WebCoreThreadWatchdog.pause();
        }
    }

    @Override
    protected void onWindowVisibilityChanged(int visibility) {
        super.onWindowVisibilityChanged(visibility);
        updateDrawingState();
    }

    void updateDrawingState() {
        if (mNativeClass == 0 || mIsPaused) return;
        if (getWindowVisibility() != VISIBLE) {
            nativeSetPauseDrawing(mNativeClass, true);
        } else if (getVisibility() != VISIBLE) {
            nativeSetPauseDrawing(mNativeClass, true);
        } else {
            nativeSetPauseDrawing(mNativeClass, false);
        }
    }

    /**
     * Call this to resume a WebView after a previous call to onPause().
     */
    public void onResume() {
        checkThread();
        if (mIsPaused) {
            mIsPaused = false;
            mWebViewCore.sendMessage(EventHub.ON_RESUME);
            if (mNativeClass != 0) {
                nativeSetPauseDrawing(mNativeClass, false);
            }
        }
        // Ensure that the watchdog has a currently valid Context to be able to display
        // a prompt dialog. For example, if the Activity was finished whilst the WebCore
        // thread was blocked and the Activity is started again, we may reuse the blocked
        // thread, but we'll have a new Activity.
        WebCoreThreadWatchdog.updateContext(mContext);
        // We get a call to onResume for new WebViews (i.e. mIsPaused will be false). We need
        // to ensure that the Watchdog thread is running for the new WebView, so call
        // it outside the if block above.
        WebCoreThreadWatchdog.resume();
    }

    /**
     * Returns true if the view is paused, meaning onPause() was called. Calling
     * onResume() sets the paused state back to false.
     * @hide
     */
    public boolean isPaused() {
        return mIsPaused;
    }

    /**
     * Call this to inform the view that memory is low so that it can
     * free any available memory.
     */
    public void freeMemory() {
        checkThread();
        mWebViewCore.sendMessage(EventHub.FREE_MEMORY);
    }

    /**
     * Clear the resource cache. Note that the cache is per-application, so
     * this will clear the cache for all WebViews used.
     *
     * @param includeDiskFiles If false, only the RAM cache is cleared.
     */
    public void clearCache(boolean includeDiskFiles) {
        checkThread();
        // Note: this really needs to be a static method as it clears cache for all
        // WebView. But we need mWebViewCore to send message to WebCore thread, so
        // we can't make this static.
        mWebViewCore.sendMessage(EventHub.CLEAR_CACHE,
                includeDiskFiles ? 1 : 0, 0);
    }

    /**
     * Make sure that clearing the form data removes the adapter from the
     * currently focused textfield if there is one.
     */
    public void clearFormData() {
        checkThread();
        if (inEditingMode()) {
            mWebTextView.setAdapterCustom(null);
        }
    }

    /**
     * Tell the WebView to clear its internal back/forward list.
     */
    public void clearHistory() {
        checkThread();
        mCallbackProxy.getBackForwardList().setClearPending();
        mWebViewCore.sendMessage(EventHub.CLEAR_HISTORY);
    }

    /**
     * Clear the SSL preferences table stored in response to proceeding with SSL
     * certificate errors.
     */
    public void clearSslPreferences() {
        checkThread();
        mWebViewCore.sendMessage(EventHub.CLEAR_SSL_PREF_TABLE);
    }

    /**
     * Return the WebBackForwardList for this WebView. This contains the
     * back/forward list for use in querying each item in the history stack.
     * This is a copy of the private WebBackForwardList so it contains only a
     * snapshot of the current state. Multiple calls to this method may return
     * different objects. The object returned from this method will not be
     * updated to reflect any new state.
     */
    public WebBackForwardList copyBackForwardList() {
        checkThread();
        return mCallbackProxy.getBackForwardList().clone();
    }

    /*
     * Highlight and scroll to the next occurance of String in findAll.
     * Wraps the page infinitely, and scrolls.  Must be called after
     * calling findAll.
     *
     * @param forward Direction to search.
     */
    public void findNext(boolean forward) {
        checkThread();
        if (0 == mNativeClass) return; // client isn't initialized
        nativeFindNext(forward);
    }

    /*
     * Find all instances of find on the page and highlight them.
     * @param find  String to find.
     * @return int  The number of occurances of the String "find"
     *              that were found.
     */
    public int findAll(String find) {
        checkThread();
        if (0 == mNativeClass) return 0; // client isn't initialized
        int result = find != null ? nativeFindAll(find.toLowerCase(),
                find.toUpperCase(), find.equalsIgnoreCase(mLastFind)) : 0;
        invalidate();
        mLastFind = find;
        return result;
    }

    /**
     * Start an ActionMode for finding text in this WebView.  Only works if this
     *              WebView is attached to the view system.
     * @param text If non-null, will be the initial text to search for.
     *             Otherwise, the last String searched for in this WebView will
     *             be used to start.
     * @param showIme If true, show the IME, assuming the user will begin typing.
     *             If false and text is non-null, perform a find all.
     * @return boolean True if the find dialog is shown, false otherwise.
     */
    public boolean showFindDialog(String text, boolean showIme) {
        checkThread();
        FindActionModeCallback callback = new FindActionModeCallback(mContext);
        if (getParent() == null || startActionMode(callback) == null) {
            // Could not start the action mode, so end Find on page
            return false;
        }
        mCachedOverlappingActionModeHeight = -1;
        mFindCallback = callback;
        setFindIsUp(true);
        mFindCallback.setWebView(this);
        if (showIme) {
            mFindCallback.showSoftInput();
        } else if (text != null) {
            mFindCallback.setText(text);
            mFindCallback.findAll();
            return true;
        }
        if (text == null) {
            text = mLastFind;
        }
        if (text != null) {
            mFindCallback.setText(text);
        }
        return true;
    }

    /**
     * Keep track of the find callback so that we can remove its titlebar if
     * necessary.
     */
    private FindActionModeCallback mFindCallback;

    /**
     * Toggle whether the find dialog is showing, for both native and Java.
     */
    private void setFindIsUp(boolean isUp) {
        mFindIsUp = isUp;
        if (0 == mNativeClass) return; // client isn't initialized
        nativeSetFindIsUp(isUp);
    }

    /**
     * Return the index of the currently highlighted match.
     */
    int findIndex() {
        if (0 == mNativeClass) return -1;
        return nativeFindIndex();
    }

    // Used to know whether the find dialog is open.  Affects whether
    // or not we draw the highlights for matches.
    private boolean mFindIsUp;

    // Keep track of the last string sent, so we can search again when find is
    // reopened.
    private String mLastFind;

    /**
     * Return the first substring consisting of the address of a physical
     * location. Currently, only addresses in the United States are detected,
     * and consist of:
     * - a house number
     * - a street name
     * - a street type (Road, Circle, etc), either spelled out or abbreviated
     * - a city name
     * - a state or territory, either spelled out or two-letter abbr.
     * - an optional 5 digit or 9 digit zip code.
     *
     * All names must be correctly capitalized, and the zip code, if present,
     * must be valid for the state. The street type must be a standard USPS
     * spelling or abbreviation. The state or territory must also be spelled
     * or abbreviated using USPS standards. The house number may not exceed
     * five digits.
     * @param addr The string to search for addresses.
     *
     * @return the address, or if no address is found, return null.
     */
    public static String findAddress(String addr) {
        checkThread();
        return findAddress(addr, false);
    }

    /**
     * @hide
     * Return the first substring consisting of the address of a physical
     * location. Currently, only addresses in the United States are detected,
     * and consist of:
     * - a house number
     * - a street name
     * - a street type (Road, Circle, etc), either spelled out or abbreviated
     * - a city name
     * - a state or territory, either spelled out or two-letter abbr.
     * - an optional 5 digit or 9 digit zip code.
     *
     * Names are optionally capitalized, and the zip code, if present,
     * must be valid for the state. The street type must be a standard USPS
     * spelling or abbreviation. The state or territory must also be spelled
     * or abbreviated using USPS standards. The house number may not exceed
     * five digits.
     * @param addr The string to search for addresses.
     * @param caseInsensitive addr Set to true to make search ignore case.
     *
     * @return the address, or if no address is found, return null.
     */
    public static String findAddress(String addr, boolean caseInsensitive) {
        return WebViewCore.nativeFindAddress(addr, caseInsensitive);
    }

    /*
     * Clear the highlighting surrounding text matches created by findAll.
     */
    public void clearMatches() {
        checkThread();
        if (mNativeClass == 0)
            return;
        nativeSetFindIsEmpty();
        invalidate();
    }

    /**
     * Called when the find ActionMode ends.
     */
    void notifyFindDialogDismissed() {
        mFindCallback = null;
        mCachedOverlappingActionModeHeight = -1;
        if (mWebViewCore == null) {
            return;
        }
        clearMatches();
        setFindIsUp(false);
        // Now that the dialog has been removed, ensure that we scroll to a
        // location that is not beyond the end of the page.
        pinScrollTo(mScrollX, mScrollY, false, 0);
        invalidate();
    }

    /**
     * Query the document to see if it contains any image references. The
     * message object will be dispatched with arg1 being set to 1 if images
     * were found and 0 if the document does not reference any images.
     * @param response The message that will be dispatched with the result.
     */
    public void documentHasImages(Message response) {
        checkThread();
        if (response == null) {
            return;
        }
        mWebViewCore.sendMessage(EventHub.DOC_HAS_IMAGES, response);
    }

    /**
     * Request the scroller to abort any ongoing animation
     *
     * @hide
     */
    public void stopScroll() {
        mScroller.forceFinished(true);
        mLastVelocity = 0;
    }

    @Override
    public void computeScroll() {
        if (mScroller.computeScrollOffset()) {
            int oldX = mScrollX;
            int oldY = mScrollY;
            int x = mScroller.getCurrX();
            int y = mScroller.getCurrY();
            invalidate();  // So we draw again

            if (!mScroller.isFinished()) {
                int rangeX = computeMaxScrollX();
                int rangeY = computeMaxScrollY();
                int overflingDistance = mOverflingDistance;

                // Use the layer's scroll data if needed.
                if (mTouchMode == TOUCH_DRAG_LAYER_MODE) {
                    oldX = mScrollingLayerRect.left;
                    oldY = mScrollingLayerRect.top;
                    rangeX = mScrollingLayerRect.right;
                    rangeY = mScrollingLayerRect.bottom;
                    // No overscrolling for layers.
                    overflingDistance = 0;
                }

                overScrollBy(x - oldX, y - oldY, oldX, oldY,
                        rangeX, rangeY,
                        overflingDistance, overflingDistance, false);

                if (mOverScrollGlow != null) {
                    mOverScrollGlow.absorbGlow(x, y, oldX, oldY, rangeX, rangeY);
                }
            } else {
                if (mTouchMode != TOUCH_DRAG_LAYER_MODE) {
                    mScrollX = x;
                    mScrollY = y;
                } else {
                    // Update the layer position instead of WebView.
                    scrollLayerTo(x, y);
                }
                abortAnimation();
                nativeSetIsScrolling(false);
                if (!mBlockWebkitViewMessages) {
                    WebViewCore.resumePriority();
                    if (!mSelectingText) {
                        WebViewCore.resumeUpdatePicture(mWebViewCore);
                    }
                }
                if (oldX != mScrollX || oldY != mScrollY) {
                    sendOurVisibleRect();
                }
            }
        } else {
            super.computeScroll();
        }
    }

    private void scrollLayerTo(int x, int y) {
        if (x == mScrollingLayerRect.left && y == mScrollingLayerRect.top) {
            return;
        }
        if (mSelectingText) {
            int dx = mScrollingLayerRect.left - x;
            int dy = mScrollingLayerRect.top - y;
            if (mSelectCursorBaseLayerId == mCurrentScrollingLayerId) {
                mSelectCursorBase.offset(dx, dy);
            }
            if (mSelectCursorExtentLayerId == mCurrentScrollingLayerId) {
                mSelectCursorExtent.offset(dx, dy);
            }
        }
        nativeScrollLayer(mCurrentScrollingLayerId, x, y);
        mScrollingLayerRect.left = x;
        mScrollingLayerRect.top = y;
        mWebViewCore.sendMessage(WebViewCore.EventHub.SCROLL_LAYER, mCurrentScrollingLayerId,
                mScrollingLayerRect);
        onScrollChanged(mScrollX, mScrollY, mScrollX, mScrollY);
        invalidate();
    }

    private static int computeDuration(int dx, int dy) {
        int distance = Math.max(Math.abs(dx), Math.abs(dy));
        int duration = distance * 1000 / STD_SPEED;
        return Math.min(duration, MAX_DURATION);
    }

    // helper to pin the scrollBy parameters (already in view coordinates)
    // returns true if the scroll was changed
    private boolean pinScrollBy(int dx, int dy, boolean animate, int animationDuration) {
        return pinScrollTo(mScrollX + dx, mScrollY + dy, animate, animationDuration);
    }
    // helper to pin the scrollTo parameters (already in view coordinates)
    // returns true if the scroll was changed
    private boolean pinScrollTo(int x, int y, boolean animate, int animationDuration) {
        x = pinLocX(x);
        y = pinLocY(y);
        int dx = x - mScrollX;
        int dy = y - mScrollY;

        if ((dx | dy) == 0) {
            return false;
        }
        abortAnimation();
        if (animate) {
            //        Log.d(LOGTAG, "startScroll: " + dx + " " + dy);
            mScroller.startScroll(mScrollX, mScrollY, dx, dy,
                    animationDuration > 0 ? animationDuration : computeDuration(dx, dy));
            awakenScrollBars(mScroller.getDuration());
            invalidate();
        } else {
            scrollTo(x, y);
        }
        return true;
    }

    // Scale from content to view coordinates, and pin.
    // Also called by jni webview.cpp
    private boolean setContentScrollBy(int cx, int cy, boolean animate) {
        if (mDrawHistory) {
            // disallow WebView to change the scroll position as History Picture
            // is used in the view system.
            // TODO: as we switchOutDrawHistory when trackball or navigation
            // keys are hit, this should be safe. Right?
            return false;
        }
        cx = contentToViewDimension(cx);
        cy = contentToViewDimension(cy);
        if (mHeightCanMeasure) {
            // move our visible rect according to scroll request
            if (cy != 0) {
                Rect tempRect = new Rect();
                calcOurVisibleRect(tempRect);
                tempRect.offset(cx, cy);
                requestRectangleOnScreen(tempRect);
            }
            // FIXME: We scroll horizontally no matter what because currently
            // ScrollView and ListView will not scroll horizontally.
            // FIXME: Why do we only scroll horizontally if there is no
            // vertical scroll?
//                Log.d(LOGTAG, "setContentScrollBy cy=" + cy);
            return cy == 0 && cx != 0 && pinScrollBy(cx, 0, animate, 0);
        } else {
            return pinScrollBy(cx, cy, animate, 0);
        }
    }

    /**
     * Called by CallbackProxy when the page starts loading.
     * @param url The URL of the page which has started loading.
     */
    /* package */ void onPageStarted(String url) {
        // every time we start a new page, we want to reset the
        // WebView certificate:  if the new site is secure, we
        // will reload it and get a new certificate set;
        // if the new site is not secure, the certificate must be
        // null, and that will be the case
        setCertificate(null);

        // reset the flag since we set to true in if need after
        // loading is see onPageFinished(Url)
        mAccessibilityScriptInjected = false;
    }

    /**
     * Called by CallbackProxy when the page finishes loading.
     * @param url The URL of the page which has finished loading.
     */
    /* package */ void onPageFinished(String url) {
        if (mPageThatNeedsToSlideTitleBarOffScreen != null) {
            // If the user is now on a different page, or has scrolled the page
            // past the point where the title bar is offscreen, ignore the
            // scroll request.
            if (mPageThatNeedsToSlideTitleBarOffScreen.equals(url)
                    && mScrollX == 0 && mScrollY == 0) {
                pinScrollTo(0, mYDistanceToSlideTitleOffScreen, true,
                        SLIDE_TITLE_DURATION);
            }
            mPageThatNeedsToSlideTitleBarOffScreen = null;
        }
        mZoomManager.onPageFinished(url);
        injectAccessibilityForUrl(url);
    }

    /**
     * This method injects accessibility in the loaded document if accessibility
     * is enabled. If JavaScript is enabled we try to inject a URL specific script.
     * If no URL specific script is found or JavaScript is disabled we fallback to
     * the default {@link AccessibilityInjector} implementation.
     * </p>
     * If the URL has the "axs" paramter set to 1 it has already done the
     * script injection so we do nothing. If the parameter is set to 0
     * the URL opts out accessibility script injection so we fall back to
     * the default {@link AccessibilityInjector}.
     * </p>
     * Note: If the user has not opted-in the accessibility script injection no scripts
     * are injected rather the default {@link AccessibilityInjector} implementation
     * is used.
     *
     * @param url The URL loaded by this {@link WebView}.
     */
    private void injectAccessibilityForUrl(String url) {
        if (mWebViewCore == null) {
            return;
        }
        AccessibilityManager accessibilityManager = AccessibilityManager.getInstance(mContext);

        if (!accessibilityManager.isEnabled()) {
            // it is possible that accessibility was turned off between reloads
            ensureAccessibilityScriptInjectorInstance(false);
            return;
        }

        if (!getSettings().getJavaScriptEnabled()) {
            // no JS so we fallback to the basic buil-in support
            ensureAccessibilityScriptInjectorInstance(true);
            return;
        }

        // check the URL "axs" parameter to choose appropriate action
        int axsParameterValue = getAxsUrlParameterValue(url);
        if (axsParameterValue == ACCESSIBILITY_SCRIPT_INJECTION_UNDEFINED) {
            boolean onDeviceScriptInjectionEnabled = (Settings.Secure.getInt(mContext
                    .getContentResolver(), Settings.Secure.ACCESSIBILITY_SCRIPT_INJECTION, 0) == 1);
            if (onDeviceScriptInjectionEnabled) {
                ensureAccessibilityScriptInjectorInstance(false);
                // neither script injected nor script injection opted out => we inject
                loadUrl(getScreenReaderInjectingJs());
                // TODO: Set this flag after successfull script injection. Maybe upon injection
                // the chooser should update the meta tag and we check it to declare success
                mAccessibilityScriptInjected = true;
            } else {
                // injection disabled so we fallback to the basic built-in support
                ensureAccessibilityScriptInjectorInstance(true);
            }
        } else if (axsParameterValue == ACCESSIBILITY_SCRIPT_INJECTION_OPTED_OUT) {
            // injection opted out so we fallback to the basic buil-in support
            ensureAccessibilityScriptInjectorInstance(true);
        } else if (axsParameterValue == ACCESSIBILITY_SCRIPT_INJECTION_PROVIDED) {
            ensureAccessibilityScriptInjectorInstance(false);
            // the URL provides accessibility but we still need to add our generic script
            loadUrl(getScreenReaderInjectingJs());
        } else {
            Log.e(LOGTAG, "Unknown URL value for the \"axs\" URL parameter: " + axsParameterValue);
        }
    }

    /**
     * Ensures the instance of the {@link AccessibilityInjector} to be present ot not.
     *
     * @param present True to ensure an insance, false to ensure no instance.
     */
    private void ensureAccessibilityScriptInjectorInstance(boolean present) {
        if (present) {
            if (mAccessibilityInjector == null) {
                mAccessibilityInjector = new AccessibilityInjector(this);
            }
        } else {
            mAccessibilityInjector = null;
        }
    }

    /**
     * Gets JavaScript that injects a screen-reader.
     *
     * @return The JavaScript snippet.
     */
    private String getScreenReaderInjectingJs() {
        String screenReaderUrl = Settings.Secure.getString(mContext.getContentResolver(),
                Settings.Secure.ACCESSIBILITY_SCREEN_READER_URL);
        return String.format(ACCESSIBILITY_SCREEN_READER_JAVASCRIPT_TEMPLATE, screenReaderUrl);
    }

    /**
     * Gets the "axs" URL parameter value.
     *
     * @param url A url to fetch the paramter from.
     * @return The parameter value if such, -1 otherwise.
     */
    private int getAxsUrlParameterValue(String url) {
        if (mMatchAxsUrlParameterPattern == null) {
            mMatchAxsUrlParameterPattern = Pattern.compile(PATTERN_MATCH_AXS_URL_PARAMETER);
        }
        Matcher matcher = mMatchAxsUrlParameterPattern.matcher(url);
        if (matcher.find()) {
            String keyValuePair = url.substring(matcher.start(), matcher.end());
            return Integer.parseInt(keyValuePair.split("=")[1]);
        }
        return -1;
    }

    /**
     * The URL of a page that sent a message to scroll the title bar off screen.
     *
     * Many mobile sites tell the page to scroll to (0,1) in order to scroll the
     * title bar off the screen.  Sometimes, the scroll position is set before
     * the page finishes loading.  Rather than scrolling while the page is still
     * loading, keep track of the URL and new scroll position so we can perform
     * the scroll once the page finishes loading.
     */
    private String mPageThatNeedsToSlideTitleBarOffScreen;

    /**
     * The destination Y scroll position to be used when the page finishes
     * loading.  See mPageThatNeedsToSlideTitleBarOffScreen.
     */
    private int mYDistanceToSlideTitleOffScreen;

    // scale from content to view coordinates, and pin
    // return true if pin caused the final x/y different than the request cx/cy,
    // and a future scroll may reach the request cx/cy after our size has
    // changed
    // return false if the view scroll to the exact position as it is requested,
    // where negative numbers are taken to mean 0
    private boolean setContentScrollTo(int cx, int cy) {
        if (mDrawHistory) {
            // disallow WebView to change the scroll position as History Picture
            // is used in the view system.
            // One known case where this is called is that WebCore tries to
            // restore the scroll position. As history Picture already uses the
            // saved scroll position, it is ok to skip this.
            return false;
        }
        int vx;
        int vy;
        if ((cx | cy) == 0) {
            // If the page is being scrolled to (0,0), do not add in the title
            // bar's height, and simply scroll to (0,0). (The only other work
            // in contentToView_ is to multiply, so this would not change 0.)
            vx = 0;
            vy = 0;
        } else {
            vx = contentToViewX(cx);
            vy = contentToViewY(cy);
        }
//        Log.d(LOGTAG, "content scrollTo [" + cx + " " + cy + "] view=[" +
//                      vx + " " + vy + "]");
        // Some mobile sites attempt to scroll the title bar off the page by
        // scrolling to (0,1).  If we are at the top left corner of the
        // page, assume this is an attempt to scroll off the title bar, and
        // animate the title bar off screen slowly enough that the user can see
        // it.
        if (cx == 0 && cy == 1 && mScrollX == 0 && mScrollY == 0
                && mTitleBar != null) {
            // FIXME: 100 should be defined somewhere as our max progress.
            if (getProgress() < 100) {
                // Wait to scroll the title bar off screen until the page has
                // finished loading.  Keep track of the URL and the destination
                // Y position
                mPageThatNeedsToSlideTitleBarOffScreen = getUrl();
                mYDistanceToSlideTitleOffScreen = vy;
            } else {
                pinScrollTo(vx, vy, true, SLIDE_TITLE_DURATION);
            }
            // Since we are animating, we have not yet reached the desired
            // scroll position.  Do not return true to request another attempt
            return false;
        }
        pinScrollTo(vx, vy, false, 0);
        // If the request was to scroll to a negative coordinate, treat it as if
        // it was a request to scroll to 0
        if ((mScrollX != vx && cx >= 0) || (mScrollY != vy && cy >= 0)) {
            return true;
        } else {
            return false;
        }
    }

    // scale from content to view coordinates, and pin
    private void spawnContentScrollTo(int cx, int cy) {
        if (mDrawHistory) {
            // disallow WebView to change the scroll position as History Picture
            // is used in the view system.
            return;
        }
        int vx = contentToViewX(cx);
        int vy = contentToViewY(cy);
        pinScrollTo(vx, vy, true, 0);
    }

    /**
     * These are from webkit, and are in content coordinate system (unzoomed)
     */
    private void contentSizeChanged(boolean updateLayout) {
        // suppress 0,0 since we usually see real dimensions soon after
        // this avoids drawing the prev content in a funny place. If we find a
        // way to consolidate these notifications, this check may become
        // obsolete
        if ((mContentWidth | mContentHeight) == 0) {
            return;
        }

        if (mHeightCanMeasure) {
            if (getMeasuredHeight() != contentToViewDimension(mContentHeight)
                    || updateLayout) {
                requestLayout();
            }
        } else if (mWidthCanMeasure) {
            if (getMeasuredWidth() != contentToViewDimension(mContentWidth)
                    || updateLayout) {
                requestLayout();
            }
        } else {
            // If we don't request a layout, try to send our view size to the
            // native side to ensure that WebCore has the correct dimensions.
            sendViewSizeZoom(false);
        }
    }

    /**
     * Set the WebViewClient that will receive various notifications and
     * requests. This will replace the current handler.
     * @param client An implementation of WebViewClient.
     */
    public void setWebViewClient(WebViewClient client) {
        checkThread();
        mCallbackProxy.setWebViewClient(client);
    }

    /**
     * Gets the WebViewClient
     * @return the current WebViewClient instance.
     *
     * @hide This is an implementation detail.
     */
    public WebViewClient getWebViewClient() {
        return mCallbackProxy.getWebViewClient();
    }

    /**
     * Register the interface to be used when content can not be handled by
     * the rendering engine, and should be downloaded instead. This will replace
     * the current handler.
     * @param listener An implementation of DownloadListener.
     */
    public void setDownloadListener(DownloadListener listener) {
        checkThread();
        mCallbackProxy.setDownloadListener(listener);
    }

    /**
     * Set the chrome handler. This is an implementation of WebChromeClient for
     * use in handling JavaScript dialogs, favicons, titles, and the progress.
     * This will replace the current handler.
     * @param client An implementation of WebChromeClient.
     */
    public void setWebChromeClient(WebChromeClient client) {
        checkThread();
        mCallbackProxy.setWebChromeClient(client);
    }

    /**
     * Gets the chrome handler.
     * @return the current WebChromeClient instance.
     *
     * @hide This is an implementation detail.
     */
    public WebChromeClient getWebChromeClient() {
        return mCallbackProxy.getWebChromeClient();
    }

    /**
     * Set the back/forward list client. This is an implementation of
     * WebBackForwardListClient for handling new items and changes in the
     * history index.
     * @param client An implementation of WebBackForwardListClient.
     * {@hide}
     */
    public void setWebBackForwardListClient(WebBackForwardListClient client) {
        mCallbackProxy.setWebBackForwardListClient(client);
    }

    /**
     * Gets the WebBackForwardListClient.
     * {@hide}
     */
    public WebBackForwardListClient getWebBackForwardListClient() {
        return mCallbackProxy.getWebBackForwardListClient();
    }

    /**
     * Set the Picture listener. This is an interface used to receive
     * notifications of a new Picture.
     * @param listener An implementation of WebView.PictureListener.
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public void setPictureListener(PictureListener listener) {
        checkThread();
        mPictureListener = listener;
    }

    /**
     * {@hide}
     */
    /* FIXME: Debug only! Remove for SDK! */
    public void externalRepresentation(Message callback) {
        mWebViewCore.sendMessage(EventHub.REQUEST_EXT_REPRESENTATION, callback);
    }

    /**
     * {@hide}
     */
    /* FIXME: Debug only! Remove for SDK! */
    public void documentAsText(Message callback) {
        mWebViewCore.sendMessage(EventHub.REQUEST_DOC_AS_TEXT, callback);
    }

    /**
     * This method injects the supplied Java object into the WebView. The
     * object is injected into the JavaScript context of the main frame, using
     * the supplied name. This allows the Java object to be accessed from
     * JavaScript. Note that that injected objects will not appear in
     * JavaScript until the page is next (re)loaded. For example:
     * <pre> webView.addJavascriptInterface(new Object(), "injectedObject");
     * webView.loadData("<!DOCTYPE html><title></title>", "text/html", null);
     * webView.loadUrl("javascript:alert(injectedObject.toString())");</pre>
     * <p><strong>IMPORTANT:</strong>
     * <ul>
     * <li> addJavascriptInterface() can be used to allow JavaScript to control
     * the host application. This is a powerful feature, but also presents a
     * security risk. Use of this method in a WebView containing untrusted
     * content could allow an attacker to manipulate the host application in
     * unintended ways, executing Java code with the permissions of the host
     * application. Use extreme care when using this method in a WebView which
     * could contain untrusted content.
     * <li> JavaScript interacts with Java object on a private, background
     * thread of the WebView. Care is therefore required to maintain thread
     * safety.</li>
     * </ul></p>
     * @param object The Java object to inject into the WebView's JavaScript
     *               context. Null values are ignored.
     * @param name The name used to expose the instance in JavaScript.
     */
    public void addJavascriptInterface(Object object, String name) {
        checkThread();
        if (object == null) {
            return;
        }
        WebViewCore.JSInterfaceData arg = new WebViewCore.JSInterfaceData();
        arg.mObject = object;
        arg.mInterfaceName = name;
        mWebViewCore.sendMessage(EventHub.ADD_JS_INTERFACE, arg);
    }

    /**
     * Removes a previously added JavaScript interface with the given name.
     * @param interfaceName The name of the interface to remove.
     */
    public void removeJavascriptInterface(String interfaceName) {
        checkThread();
        if (mWebViewCore != null) {
            WebViewCore.JSInterfaceData arg = new WebViewCore.JSInterfaceData();
            arg.mInterfaceName = interfaceName;
            mWebViewCore.sendMessage(EventHub.REMOVE_JS_INTERFACE, arg);
        }
    }

    /**
     * Return the WebSettings object used to control the settings for this
     * WebView.
     * @return A WebSettings object that can be used to control this WebView's
     *         settings.
     */
    public WebSettings getSettings() {
        checkThread();
        return (mWebViewCore != null) ? mWebViewCore.getSettings() : null;
    }

   /**
    * Return the list of currently loaded plugins.
    * @return The list of currently loaded plugins.
    *
    * @hide
    * @deprecated This was used for Gears, which has been deprecated.
    */
    @Deprecated
    public static synchronized PluginList getPluginList() {
        checkThread();
        return new PluginList();
    }

   /**
    * @hide
    * @deprecated This was used for Gears, which has been deprecated.
    */
    @Deprecated
    public void refreshPlugins(boolean reloadOpenPages) {
        checkThread();
    }

    //-------------------------------------------------------------------------
    // Override View methods
    //-------------------------------------------------------------------------

    @Override
    protected void finalize() throws Throwable {
        try {
            if (mNativeClass != 0) {
                mPrivateHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        destroy();
                    }
                });
            }
        } finally {
            super.finalize();
        }
    }

    @Override
    protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
        if (child == mTitleBar) {
            // When drawing the title bar, move it horizontally to always show
            // at the top of the WebView.
            mTitleBar.offsetLeftAndRight(mScrollX - mTitleBar.getLeft());
            int newTop = 0;
            if (mTitleGravity == Gravity.NO_GRAVITY) {
                newTop = Math.min(0, mScrollY);
            } else if (mTitleGravity == Gravity.TOP) {
                newTop = mScrollY;
            }
            mTitleBar.setBottom(newTop + mTitleBar.getHeight());
            mTitleBar.setTop(newTop);
        }
        return super.drawChild(canvas, child, drawingTime);
    }

    private void drawContent(Canvas canvas, boolean drawRings) {
        drawCoreAndCursorRing(canvas, mBackgroundColor,
                mDrawCursorRing && drawRings);
    }

    /**
     * Draw the background when beyond bounds
     * @param canvas Canvas to draw into
     */
    private void drawOverScrollBackground(Canvas canvas) {
        if (mOverScrollBackground == null) {
            mOverScrollBackground = new Paint();
            Bitmap bm = BitmapFactory.decodeResource(
                    mContext.getResources(),
                    com.android.internal.R.drawable.status_bar_background);
            mOverScrollBackground.setShader(new BitmapShader(bm,
                    Shader.TileMode.REPEAT, Shader.TileMode.REPEAT));
            mOverScrollBorder = new Paint();
            mOverScrollBorder.setStyle(Paint.Style.STROKE);
            mOverScrollBorder.setStrokeWidth(0);
            mOverScrollBorder.setColor(0xffbbbbbb);
        }

        int top = 0;
        int right = computeRealHorizontalScrollRange();
        int bottom = top + computeRealVerticalScrollRange();
        // first draw the background and anchor to the top of the view
        canvas.save();
        canvas.translate(mScrollX, mScrollY);
        canvas.clipRect(-mScrollX, top - mScrollY, right - mScrollX, bottom
                - mScrollY, Region.Op.DIFFERENCE);
        canvas.drawPaint(mOverScrollBackground);
        canvas.restore();
        // then draw the border
        canvas.drawRect(-1, top - 1, right, bottom, mOverScrollBorder);
        // next clip the region for the content
        canvas.clipRect(0, top, right, bottom);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (inFullScreenMode()) {
            return; // no need to draw anything if we aren't visible.
        }
        // if mNativeClass is 0, the WebView is either destroyed or not
        // initialized. In either case, just draw the background color and return
        if (mNativeClass == 0) {
            canvas.drawColor(mBackgroundColor);
            return;
        }

        // if both mContentWidth and mContentHeight are 0, it means there is no
        // valid Picture passed to WebView yet. This can happen when WebView
        // just starts. Draw the background and return.
        if ((mContentWidth | mContentHeight) == 0 && mHistoryPicture == null) {
            canvas.drawColor(mBackgroundColor);
            return;
        }

        if (canvas.isHardwareAccelerated()) {
            mZoomManager.setHardwareAccelerated();
        } else {
            mWebViewCore.resumeWebKitDraw();
        }

        int saveCount = canvas.save();
        if (mInOverScrollMode && !getSettings()
                .getUseWebViewBackgroundForOverscrollBackground()) {
            drawOverScrollBackground(canvas);
        }
        if (mTitleBar != null) {
            canvas.translate(0, getTitleHeight());
        }
        boolean drawJavaRings = !mTouchHighlightRegion.isEmpty()
                && (mTouchMode == TOUCH_INIT_MODE
                || mTouchMode == TOUCH_SHORTPRESS_START_MODE
                || mTouchMode == TOUCH_SHORTPRESS_MODE
                || mTouchMode == TOUCH_DONE_MODE);
        boolean drawNativeRings = !drawJavaRings;
        if (sDisableNavcache) {
            drawNativeRings = !drawJavaRings && !isInTouchMode();
        }
        drawContent(canvas, drawNativeRings);
        canvas.restoreToCount(saveCount);

        if (AUTO_REDRAW_HACK && mAutoRedraw) {
            invalidate();
        }
        mWebViewCore.signalRepaintDone();

        if (mOverScrollGlow != null && mOverScrollGlow.drawEdgeGlows(canvas)) {
            invalidate();
        }

        // paint the highlight in the end
        if (drawJavaRings) {
            long delay = System.currentTimeMillis() - mTouchHighlightRequested;
            if (delay < ViewConfiguration.getTapTimeout()) {
                Rect r = mTouchHighlightRegion.getBounds();
                postInvalidateDelayed(delay, r.left, r.top, r.right, r.bottom);
            } else {
                RegionIterator iter = new RegionIterator(mTouchHighlightRegion);
                Rect r = new Rect();
                while (iter.next(r)) {
                    canvas.drawRect(r, mTouchHightlightPaint);
                }
            }
        }
        if (DEBUG_TOUCH_HIGHLIGHT) {
            if (getSettings().getNavDump()) {
                if ((mTouchHighlightX | mTouchHighlightY) != 0) {
                    if (mTouchCrossHairColor == null) {
                        mTouchCrossHairColor = new Paint();
                        mTouchCrossHairColor.setColor(Color.RED);
                    }
                    canvas.drawLine(mTouchHighlightX - mNavSlop,
                            mTouchHighlightY - mNavSlop, mTouchHighlightX
                                    + mNavSlop + 1, mTouchHighlightY + mNavSlop
                                    + 1, mTouchCrossHairColor);
                    canvas.drawLine(mTouchHighlightX + mNavSlop + 1,
                            mTouchHighlightY - mNavSlop, mTouchHighlightX
                                    - mNavSlop,
                            mTouchHighlightY + mNavSlop + 1,
                            mTouchCrossHairColor);
                }
            }
        }
    }

    private void removeTouchHighlight() {
        mWebViewCore.removeMessages(EventHub.HIT_TEST);
        mPrivateHandler.removeMessages(HIT_TEST_RESULT);
        setTouchHighlightRects(null);
    }

    @Override
    public void setLayoutParams(ViewGroup.LayoutParams params) {
        if (params.height == LayoutParams.WRAP_CONTENT) {
            mWrapContent = true;
        }
        super.setLayoutParams(params);
    }

    @Override
    public boolean performLongClick() {
        // performLongClick() is the result of a delayed message. If we switch
        // to windows overview, the WebView will be temporarily removed from the
        // view system. In that case, do nothing.
        if (getParent() == null) return false;

        // A multi-finger gesture can look like a long press; make sure we don't take
        // long press actions if we're scaling.
        final ScaleGestureDetector detector = mZoomManager.getMultiTouchGestureDetector();
        if (detector != null && detector.isInProgress()) {
            return false;
        }

        if (mNativeClass != 0 && nativeCursorIsTextInput()) {
            // Send the click so that the textfield is in focus
            centerKeyPressOnTextField();
            rebuildWebTextView();
        } else {
            clearTextEntry();
        }
        if (inEditingMode()) {
            // Since we just called rebuildWebTextView, the layout is not set
            // properly.  Update it so it can correctly find the word to select.
            mWebTextView.ensureLayout();
            // Provide a touch down event to WebTextView, which will allow it
            // to store the location to use in performLongClick.
            AbsoluteLayout.LayoutParams params
                    = (AbsoluteLayout.LayoutParams) mWebTextView.getLayoutParams();
            MotionEvent fake = MotionEvent.obtain(mLastTouchTime,
                    mLastTouchTime, MotionEvent.ACTION_DOWN,
                    mLastTouchX - params.x + mScrollX,
                    mLastTouchY - params.y + mScrollY, 0);
            mWebTextView.dispatchTouchEvent(fake);
            return mWebTextView.performLongClick();
        }
        if (mSelectingText) return false; // long click does nothing on selection
        /* if long click brings up a context menu, the super function
         * returns true and we're done. Otherwise, nothing happened when
         * the user clicked. */
        if (super.performLongClick()) {
            return true;
        }
        /* In the case where the application hasn't already handled the long
         * click action, look for a word under the  click. If one is found,
         * animate the text selection into view.
         * FIXME: no animation code yet */
        final boolean isSelecting = selectText();
        if (isSelecting) {
            performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
        } else if (focusCandidateIsEditableText()) {
            mSelectCallback = new SelectActionModeCallback();
            mSelectCallback.setWebView(this);
            mSelectCallback.setTextSelected(false);
            startActionMode(mSelectCallback);
        }
        return isSelecting;
    }

    /**
     * Select the word at the last click point.
     *
     * @hide This is an implementation detail.
     */
    public boolean selectText() {
        int x = viewToContentX(mLastTouchX + mScrollX);
        int y = viewToContentY(mLastTouchY + mScrollY);
        return selectText(x, y);
    }

    /**
     * Select the word at the indicated content coordinates.
     */
    boolean selectText(int x, int y) {
        mWebViewCore.sendMessage(EventHub.SELECT_WORD_AT, x, y);
        return true;
    }

    private int mOrientation = Configuration.ORIENTATION_UNDEFINED;

    @Override
    protected void onConfigurationChanged(Configuration newConfig) {
        mCachedOverlappingActionModeHeight = -1;
        if (mSelectingText && mOrientation != newConfig.orientation) {
            selectionDone();
        }
        mOrientation = newConfig.orientation;
        if (mWebViewCore != null && !mBlockWebkitViewMessages) {
            mWebViewCore.sendMessage(EventHub.CLEAR_CONTENT);
        }
    }

    /**
     * Keep track of the Callback so we can end its ActionMode or remove its
     * titlebar.
     */
    private SelectActionModeCallback mSelectCallback;

    // These values are possible options for didUpdateWebTextViewDimensions.
    private static final int FULLY_ON_SCREEN = 0;
    private static final int INTERSECTS_SCREEN = 1;
    private static final int ANYWHERE = 2;

    /**
     * Check to see if the focused textfield/textarea is still on screen.  If it
     * is, update the the dimensions and location of WebTextView.  Otherwise,
     * remove the WebTextView.  Should be called when the zoom level changes.
     * @param intersection How to determine whether the textfield/textarea is
     *        still on screen.
     * @return boolean True if the textfield/textarea is still on screen and the
     *         dimensions/location of WebTextView have been updated.
     */
    private boolean didUpdateWebTextViewDimensions(int intersection) {
        Rect contentBounds = nativeFocusCandidateNodeBounds();
        Rect vBox = contentToViewRect(contentBounds);
        Rect visibleRect = new Rect();
        calcOurVisibleRect(visibleRect);
        offsetByLayerScrollPosition(vBox);
        // If the textfield is on screen, place the WebTextView in
        // its new place, accounting for our new scroll/zoom values,
        // and adjust its textsize.
        boolean onScreen;
        switch (intersection) {
            case FULLY_ON_SCREEN:
                onScreen = visibleRect.contains(vBox);
                break;
            case INTERSECTS_SCREEN:
                onScreen = Rect.intersects(visibleRect, vBox);
                break;
            case ANYWHERE:
                onScreen = true;
                break;
            default:
                throw new AssertionError(
                        "invalid parameter passed to didUpdateWebTextViewDimensions");
        }
        if (onScreen) {
            mWebTextView.setRect(vBox.left, vBox.top, vBox.width(),
                    vBox.height());
            mWebTextView.updateTextSize();
            updateWebTextViewPadding();
            return true;
        } else {
            // The textfield is now off screen.  The user probably
            // was not zooming to see the textfield better.  Remove
            // the WebTextView.  If the user types a key, and the
            // textfield is still in focus, we will reconstruct
            // the WebTextView and scroll it back on screen.
            mWebTextView.remove();
            return false;
        }
    }

    private void offsetByLayerScrollPosition(Rect box) {
        if ((mCurrentScrollingLayerId != 0)
                && (mCurrentScrollingLayerId == nativeFocusCandidateLayerId())) {
            box.offsetTo(box.left - mScrollingLayerRect.left,
                    box.top - mScrollingLayerRect.top);
        }
    }

    void setBaseLayer(int layer, Region invalRegion, boolean showVisualIndicator,
            boolean isPictureAfterFirstLayout) {
        if (mNativeClass == 0)
            return;
        boolean queueFull;
        queueFull = nativeSetBaseLayer(mNativeClass, layer, invalRegion,
                                       showVisualIndicator, isPictureAfterFirstLayout);

        if (layer == 0 || isPictureAfterFirstLayout) {
            mWebViewCore.resumeWebKitDraw();
        } else if (queueFull) {
            // temporarily disable webkit draw throttling
            // TODO: re-enable
            // mWebViewCore.pauseWebKitDraw();
        }

        if (mHTML5VideoViewProxy != null) {
            mHTML5VideoViewProxy.setBaseLayer(layer);
        }
    }

    int getBaseLayer() {
        if (mNativeClass == 0) {
            return 0;
        }
        return nativeGetBaseLayer();
    }

    private void onZoomAnimationStart() {
        // If it is in password mode, turn it off so it does not draw misplaced.
        if (inEditingMode()) {
            mWebTextView.setVisibility(INVISIBLE);
        }
    }

    private void onZoomAnimationEnd() {
        // adjust the edit text view if needed
        if (inEditingMode()
                && didUpdateWebTextViewDimensions(FULLY_ON_SCREEN)) {
            // If it is a password field, start drawing the WebTextView once
            // again.
            mWebTextView.setVisibility(VISIBLE);
        }
    }

    void onFixedLengthZoomAnimationStart() {
        WebViewCore.pauseUpdatePicture(getWebViewCore());
        onZoomAnimationStart();
    }

    void onFixedLengthZoomAnimationEnd() {
        if (!mBlockWebkitViewMessages && !mSelectingText) {
            WebViewCore.resumeUpdatePicture(mWebViewCore);
        }
        onZoomAnimationEnd();
    }

    private static final int ZOOM_BITS = Paint.FILTER_BITMAP_FLAG |
                                         Paint.DITHER_FLAG |
                                         Paint.SUBPIXEL_TEXT_FLAG;
    private static final int SCROLL_BITS = Paint.FILTER_BITMAP_FLAG |
                                           Paint.DITHER_FLAG;

    private final DrawFilter mZoomFilter =
            new PaintFlagsDrawFilter(ZOOM_BITS, Paint.LINEAR_TEXT_FLAG);
    // If we need to trade better quality for speed, set mScrollFilter to null
    private final DrawFilter mScrollFilter =
            new PaintFlagsDrawFilter(SCROLL_BITS, 0);

    private void drawCoreAndCursorRing(Canvas canvas, int color,
        boolean drawCursorRing) {
        if (mDrawHistory) {
            canvas.scale(mZoomManager.getScale(), mZoomManager.getScale());
            canvas.drawPicture(mHistoryPicture);
            return;
        }
        if (mNativeClass == 0) return;

        boolean animateZoom = mZoomManager.isFixedLengthAnimationInProgress();
        boolean animateScroll = ((!mScroller.isFinished()
                || mVelocityTracker != null)
                && (mTouchMode != TOUCH_DRAG_MODE ||
                mHeldMotionless != MOTIONLESS_TRUE))
                || mDeferTouchMode == TOUCH_DRAG_MODE;
        if (mTouchMode == TOUCH_DRAG_MODE) {
            if (mHeldMotionless == MOTIONLESS_PENDING) {
                mPrivateHandler.removeMessages(DRAG_HELD_MOTIONLESS);
                mPrivateHandler.removeMessages(AWAKEN_SCROLL_BARS);
                mHeldMotionless = MOTIONLESS_FALSE;
            }
            if (mHeldMotionless == MOTIONLESS_FALSE) {
                mPrivateHandler.sendMessageDelayed(mPrivateHandler
                        .obtainMessage(DRAG_HELD_MOTIONLESS), MOTIONLESS_TIME);
                mPrivateHandler.sendMessageDelayed(mPrivateHandler
                        .obtainMessage(AWAKEN_SCROLL_BARS),
                            ViewConfiguration.getScrollDefaultDelay());
                mHeldMotionless = MOTIONLESS_PENDING;
            }
        }
        int saveCount = canvas.save();
        if (animateZoom) {
            mZoomManager.animateZoom(canvas);
        } else if (!canvas.isHardwareAccelerated()) {
            canvas.scale(mZoomManager.getScale(), mZoomManager.getScale());
        }

        boolean UIAnimationsRunning = false;
        // Currently for each draw we compute the animation values;
        // We may in the future decide to do that independently.
        if (mNativeClass != 0 && !canvas.isHardwareAccelerated()
                && nativeEvaluateLayersAnimations(mNativeClass)) {
            UIAnimationsRunning = true;
            // If we have unfinished (or unstarted) animations,
            // we ask for a repaint. We only need to do this in software
            // rendering (with hardware rendering we already have a different
            // method of requesting a repaint)
            mWebViewCore.sendMessage(EventHub.NOTIFY_ANIMATION_STARTED);
            invalidate();
        }

        // decide which adornments to draw
        int extras = DRAW_EXTRAS_NONE;
        if (mFindIsUp) {
            extras = DRAW_EXTRAS_FIND;
        } else if (mSelectingText) {
            extras = DRAW_EXTRAS_SELECTION;
        } else if (drawCursorRing) {
            extras = DRAW_EXTRAS_CURSOR_RING;
        }
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "mFindIsUp=" + mFindIsUp
                    + " mSelectingText=" + mSelectingText
                    + " nativePageShouldHandleShiftAndArrows()="
                    + nativePageShouldHandleShiftAndArrows()
                    + " animateZoom=" + animateZoom
                    + " extras=" + extras);
        }

        calcOurContentVisibleRectF(mVisibleContentRect);
        if (canvas.isHardwareAccelerated()) {
            Rect glRectViewport = mGLViewportEmpty ? null : mGLRectViewport;
            Rect viewRectViewport = mGLViewportEmpty ? null : mViewRectViewport;

            int functor = nativeGetDrawGLFunction(mNativeClass, glRectViewport,
                    viewRectViewport, mVisibleContentRect, getScale(), extras);
            ((HardwareCanvas) canvas).callDrawGLFunction(functor);
            if (mHardwareAccelSkia != getSettings().getHardwareAccelSkiaEnabled()) {
                mHardwareAccelSkia = getSettings().getHardwareAccelSkiaEnabled();
                nativeUseHardwareAccelSkia(mHardwareAccelSkia);
            }

        } else {
            DrawFilter df = null;
            if (mZoomManager.isZoomAnimating() || UIAnimationsRunning) {
                df = mZoomFilter;
            } else if (animateScroll) {
                df = mScrollFilter;
            }
            canvas.setDrawFilter(df);
            // XXX: Revisit splitting content.  Right now it causes a
            // synchronization problem with layers.
            int content = nativeDraw(canvas, mVisibleContentRect, color,
                    extras, false);
            canvas.setDrawFilter(null);
            if (!mBlockWebkitViewMessages && content != 0) {
                mWebViewCore.sendMessage(EventHub.SPLIT_PICTURE_SET, content, 0);
            }
        }

        canvas.restoreToCount(saveCount);
        if (mSelectingText) {
            drawTextSelectionHandles(canvas);
        }

        if (extras == DRAW_EXTRAS_CURSOR_RING) {
            if (mTouchMode == TOUCH_SHORTPRESS_START_MODE) {
                mTouchMode = TOUCH_SHORTPRESS_MODE;
            }
        }
        if (mFocusSizeChanged) {
            mFocusSizeChanged = false;
            // If we are zooming, this will get handled above, when the zoom
            // finishes.  We also do not need to do this unless the WebTextView
            // is showing. With hardware acceleration, the pageSwapCallback()
            // updates the WebTextView position in sync with page swapping
            if (!canvas.isHardwareAccelerated() && !animateZoom && inEditingMode()) {
                didUpdateWebTextViewDimensions(ANYWHERE);
            }
        }
    }

    private void drawTextSelectionHandles(Canvas canvas) {
        if (mSelectHandleLeft == null) {
            mSelectHandleLeft = mContext.getResources().getDrawable(
                    com.android.internal.R.drawable.text_select_handle_left);
        }
        int[] handles = new int[4];
        getSelectionHandles(handles);
        int start_x = contentToViewDimension(handles[0]);
        int start_y = contentToViewDimension(handles[1]);
        int end_x = contentToViewDimension(handles[2]);
        int end_y = contentToViewDimension(handles[3]);
        // Magic formula copied from TextView
        start_x -= (mSelectHandleLeft.getIntrinsicWidth() * 3) / 4;
        mSelectHandleLeft.setBounds(start_x, start_y,
                start_x + mSelectHandleLeft.getIntrinsicWidth(),
                start_y + mSelectHandleLeft.getIntrinsicHeight());
        if (mSelectHandleRight == null) {
            mSelectHandleRight = mContext.getResources().getDrawable(
                    com.android.internal.R.drawable.text_select_handle_right);
        }
        end_x -= mSelectHandleRight.getIntrinsicWidth() / 4;
        mSelectHandleRight.setBounds(end_x, end_y,
                end_x + mSelectHandleRight.getIntrinsicWidth(),
                end_y + mSelectHandleRight.getIntrinsicHeight());
        mSelectHandleLeft.draw(canvas);
        mSelectHandleRight.draw(canvas);
    }

    /**
     * Takes an int[4] array as an output param with the values being
     * startX, startY, endX, endY
     */
    private void getSelectionHandles(int[] handles) {
        handles[0] = mSelectCursorBase.right;
        handles[1] = mSelectCursorBase.bottom -
                (mSelectCursorBase.height() / 4);
        handles[2] = mSelectCursorExtent.left;
        handles[3] = mSelectCursorExtent.bottom
                - (mSelectCursorExtent.height() / 4);
        if (!nativeIsBaseFirst(mNativeClass)) {
            int swap = handles[0];
            handles[0] = handles[2];
            handles[2] = swap;
            swap = handles[1];
            handles[1] = handles[3];
            handles[3] = swap;
        }
    }

    // draw history
    private boolean mDrawHistory = false;
    private Picture mHistoryPicture = null;
    private int mHistoryWidth = 0;
    private int mHistoryHeight = 0;

    // Only check the flag, can be called from WebCore thread
    boolean drawHistory() {
        return mDrawHistory;
    }

    int getHistoryPictureWidth() {
        return (mHistoryPicture != null) ? mHistoryPicture.getWidth() : 0;
    }

    // Should only be called in UI thread
    void switchOutDrawHistory() {
        if (null == mWebViewCore) return; // CallbackProxy may trigger this
        if (mDrawHistory && (getProgress() == 100 || nativeHasContent())) {
            mDrawHistory = false;
            mHistoryPicture = null;
            invalidate();
            int oldScrollX = mScrollX;
            int oldScrollY = mScrollY;
            mScrollX = pinLocX(mScrollX);
            mScrollY = pinLocY(mScrollY);
            if (oldScrollX != mScrollX || oldScrollY != mScrollY) {
                onScrollChanged(mScrollX, mScrollY, oldScrollX, oldScrollY);
            } else {
                sendOurVisibleRect();
            }
        }
    }

    WebViewCore.CursorData cursorData() {
        WebViewCore.CursorData result = cursorDataNoPosition();
        Point position = nativeCursorPosition();
        result.mX = position.x;
        result.mY = position.y;
        return result;
    }

    WebViewCore.CursorData cursorDataNoPosition() {
        WebViewCore.CursorData result = new WebViewCore.CursorData();
        result.mMoveGeneration = nativeMoveGeneration();
        result.mFrame = nativeCursorFramePointer();
        return result;
    }

    /**
     *  Delete text from start to end in the focused textfield. If there is no
     *  focus, or if start == end, silently fail.  If start and end are out of
     *  order, swap them.
     *  @param  start   Beginning of selection to delete.
     *  @param  end     End of selection to delete.
     */
    /* package */ void deleteSelection(int start, int end) {
        mTextGeneration++;
        WebViewCore.TextSelectionData data
                = new WebViewCore.TextSelectionData(start, end, 0);
        mWebViewCore.sendMessage(EventHub.DELETE_SELECTION, mTextGeneration, 0,
                data);
    }

    /**
     *  Set the selection to (start, end) in the focused textfield. If start and
     *  end are out of order, swap them.
     *  @param  start   Beginning of selection.
     *  @param  end     End of selection.
     */
    /* package */ void setSelection(int start, int end) {
        if (mWebViewCore != null) {
            mWebViewCore.sendMessage(EventHub.SET_SELECTION, start, end);
        }
    }

    @Override
    public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
        outAttrs.inputType = EditorInfo.IME_FLAG_NO_FULLSCREEN
                | EditorInfo.TYPE_CLASS_TEXT
                | EditorInfo.TYPE_TEXT_VARIATION_WEB_EDIT_TEXT
                | EditorInfo.TYPE_TEXT_FLAG_MULTI_LINE
                | EditorInfo.TYPE_TEXT_FLAG_AUTO_CORRECT
                | EditorInfo.TYPE_TEXT_FLAG_CAP_SENTENCES;
        outAttrs.imeOptions = EditorInfo.IME_ACTION_NONE;

        if (mInputConnection == null) {
            mInputConnection = new WebViewInputConnection();
        }
        outAttrs.initialCapsMode = mInputConnection.getCursorCapsMode(InputType.TYPE_CLASS_TEXT);
        return mInputConnection;
    }

    /**
     * Called in response to a message from webkit telling us that the soft
     * keyboard should be launched.
     */
    private void displaySoftKeyboard(boolean isTextView) {
        InputMethodManager imm = (InputMethodManager)
                getContext().getSystemService(Context.INPUT_METHOD_SERVICE);

        // bring it back to the default level scale so that user can enter text
        boolean zoom = mZoomManager.getScale() < mZoomManager.getDefaultScale();
        if (zoom) {
            mZoomManager.setZoomCenter(mLastTouchX, mLastTouchY);
            mZoomManager.setZoomScale(mZoomManager.getDefaultScale(), false);
        }
        if (isTextView) {
            rebuildWebTextView();
            if (inEditingMode()) {
                imm.showSoftInput(mWebTextView, 0, mWebTextView.getResultReceiver());
                if (zoom) {
                    didUpdateWebTextViewDimensions(INTERSECTS_SCREEN);
                }
                return;
            }
        }
        // Used by plugins and contentEditable.
        // Also used if the navigation cache is out of date, and
        // does not recognize that a textfield is in focus.  In that
        // case, use WebView as the targeted view.
        // see http://b/issue?id=2457459
        imm.showSoftInput(this, 0);
    }

    // Called by WebKit to instruct the UI to hide the keyboard
    private void hideSoftKeyboard() {
        InputMethodManager imm = InputMethodManager.peekInstance();
        if (imm != null && (imm.isActive(this)
                || (inEditingMode() && imm.isActive(mWebTextView)))) {
            imm.hideSoftInputFromWindow(this.getWindowToken(), 0);
        }
    }

    /*
     * This method checks the current focus and cursor and potentially rebuilds
     * mWebTextView to have the appropriate properties, such as password,
     * multiline, and what text it contains.  It also removes it if necessary.
     */
    /* package */ void rebuildWebTextView() {
        if (!sEnableWebTextView) {
            return; // always use WebKit's text entry
        }
        // If the WebView does not have focus, do nothing until it gains focus.
        if (!hasFocus() && (null == mWebTextView || !mWebTextView.hasFocus())) {
            return;
        }
        boolean alreadyThere = inEditingMode();
        // inEditingMode can only return true if mWebTextView is non-null,
        // so we can safely call remove() if (alreadyThere)
        if (0 == mNativeClass || !nativeFocusCandidateIsTextInput()) {
            if (alreadyThere) {
                mWebTextView.remove();
            }
            return;
        }
        // At this point, we know we have found an input field, so go ahead
        // and create the WebTextView if necessary.
        if (mWebTextView == null) {
            mWebTextView = new WebTextView(mContext, WebView.this, mAutoFillData.getQueryId());
            // Initialize our generation number.
            mTextGeneration = 0;
        }
        mWebTextView.updateTextSize();
        updateWebTextViewPosition();
        String text = nativeFocusCandidateText();
        int nodePointer = nativeFocusCandidatePointer();
        // This needs to be called before setType, which may call
        // requestFormData, and it needs to have the correct nodePointer.
        mWebTextView.setNodePointer(nodePointer);
        mWebTextView.setType(nativeFocusCandidateType());
        // Gravity needs to be set after setType
        mWebTextView.setGravityForRtl(nativeFocusCandidateIsRtlText());
        if (null == text) {
            if (DebugFlags.WEB_VIEW) {
                Log.v(LOGTAG, "rebuildWebTextView null == text");
            }
            text = "";
        }
        mWebTextView.setTextAndKeepSelection(text);
        InputMethodManager imm = InputMethodManager.peekInstance();
        if (imm != null && imm.isActive(mWebTextView)) {
            imm.restartInput(mWebTextView);
            mWebTextView.clearComposingText();
        }
        if (isFocused()) {
            mWebTextView.requestFocus();
        }
    }

    private void updateWebTextViewPosition() {
        Rect visibleRect = new Rect();
        calcOurContentVisibleRect(visibleRect);
        // Note that sendOurVisibleRect calls viewToContent, so the coordinates
        // should be in content coordinates.
        Rect bounds = nativeFocusCandidateNodeBounds();
        Rect vBox = contentToViewRect(bounds);
        offsetByLayerScrollPosition(vBox);
        mWebTextView.setRect(vBox.left, vBox.top, vBox.width(), vBox.height());
        if (!Rect.intersects(bounds, visibleRect)) {
            revealSelection();
        }
        updateWebTextViewPadding();
    }

    /**
     * Update the padding of mWebTextView based on the native textfield/textarea
     */
    void updateWebTextViewPadding() {
        Rect paddingRect = nativeFocusCandidatePaddingRect();
        if (paddingRect != null) {
            // Use contentToViewDimension since these are the dimensions of
            // the padding.
            mWebTextView.setPadding(
                    contentToViewDimension(paddingRect.left),
                    contentToViewDimension(paddingRect.top),
                    contentToViewDimension(paddingRect.right),
                    contentToViewDimension(paddingRect.bottom));
        }
    }

    /**
     * Tell webkit to put the cursor on screen.
     */
    /* package */ void revealSelection() {
        if (mWebViewCore != null) {
            mWebViewCore.sendMessage(EventHub.REVEAL_SELECTION);
        }
    }

    /**
     * Called by WebTextView to find saved form data associated with the
     * textfield
     * @param name Name of the textfield.
     * @param nodePointer Pointer to the node of the textfield, so it can be
     *          compared to the currently focused textfield when the data is
     *          retrieved.
     * @param autoFillable true if WebKit has determined this field is part of
     *          a form that can be auto filled.
     * @param autoComplete true if the attribute "autocomplete" is set to true
     *          on the textfield.
     */
    /* package */ void requestFormData(String name, int nodePointer,
            boolean autoFillable, boolean autoComplete) {
        if (mWebViewCore.getSettings().getSaveFormData()) {
            Message update = mPrivateHandler.obtainMessage(REQUEST_FORM_DATA);
            update.arg1 = nodePointer;
            RequestFormData updater = new RequestFormData(name, getUrl(),
                    update, autoFillable, autoComplete);
            Thread t = new Thread(updater);
            t.start();
        }
    }

    /**
     * Pass a message to find out the <label> associated with the <input>
     * identified by nodePointer
     * @param framePointer Pointer to the frame containing the <input> node
     * @param nodePointer Pointer to the node for which a <label> is desired.
     */
    /* package */ void requestLabel(int framePointer, int nodePointer) {
        mWebViewCore.sendMessage(EventHub.REQUEST_LABEL, framePointer,
                nodePointer);
    }

    /*
     * This class requests an Adapter for the WebTextView which shows past
     * entries stored in the database.  It is a Runnable so that it can be done
     * in its own thread, without slowing down the UI.
     */
    private class RequestFormData implements Runnable {
        private String mName;
        private String mUrl;
        private Message mUpdateMessage;
        private boolean mAutoFillable;
        private boolean mAutoComplete;
        private WebSettings mWebSettings;

        public RequestFormData(String name, String url, Message msg,
                boolean autoFillable, boolean autoComplete) {
            mName = name;
            mUrl = WebTextView.urlForAutoCompleteData(url);
            mUpdateMessage = msg;
            mAutoFillable = autoFillable;
            mAutoComplete = autoComplete;
            mWebSettings = getSettings();
        }

        @Override
        public void run() {
            ArrayList<String> pastEntries = new ArrayList<String>();

            if (mAutoFillable) {
                // Note that code inside the adapter click handler in WebTextView depends
                // on the AutoFill item being at the top of the drop down list. If you change
                // the order, make sure to do it there too!
                if (mWebSettings != null && mWebSettings.getAutoFillProfile() != null) {
                    pastEntries.add(getResources().getText(
                            com.android.internal.R.string.autofill_this_form).toString() +
                            " " +
                            mAutoFillData.getPreviewString());
                    mWebTextView.setAutoFillProfileIsSet(true);
                } else {
                    // There is no autofill profile set up yet, so add an option that
                    // will invite the user to set their profile up.
                    pastEntries.add(getResources().getText(
                            com.android.internal.R.string.setup_autofill).toString());
                    mWebTextView.setAutoFillProfileIsSet(false);
                }
            }

            if (mAutoComplete) {
                pastEntries.addAll(mDatabase.getFormData(mUrl, mName));
            }

            if (pastEntries.size() > 0) {
                AutoCompleteAdapter adapter = new
                        AutoCompleteAdapter(mContext, pastEntries);
                mUpdateMessage.obj = adapter;
                mUpdateMessage.sendToTarget();
            }
        }
    }

    /**
     * Dump the display tree to "/sdcard/displayTree.txt"
     *
     * @hide debug only
     */
    public void dumpDisplayTree() {
        nativeDumpDisplayTree(getUrl());
    }

    /**
     * Dump the dom tree to adb shell if "toFile" is False, otherwise dump it to
     * "/sdcard/domTree.txt"
     *
     * @hide debug only
     */
    public void dumpDomTree(boolean toFile) {
        mWebViewCore.sendMessage(EventHub.DUMP_DOMTREE, toFile ? 1 : 0, 0);
    }

    /**
     * Dump the render tree to adb shell if "toFile" is False, otherwise dump it
     * to "/sdcard/renderTree.txt"
     *
     * @hide debug only
     */
    public void dumpRenderTree(boolean toFile) {
        mWebViewCore.sendMessage(EventHub.DUMP_RENDERTREE, toFile ? 1 : 0, 0);
    }

    /**
     * Called by DRT on UI thread, need to proxy to WebCore thread.
     *
     * @hide debug only
     */
    public void useMockDeviceOrientation() {
        mWebViewCore.sendMessage(EventHub.USE_MOCK_DEVICE_ORIENTATION);
    }

    /**
     * Called by DRT on WebCore thread.
     *
     * @hide debug only
     */
    public void setMockDeviceOrientation(boolean canProvideAlpha, double alpha,
            boolean canProvideBeta, double beta, boolean canProvideGamma, double gamma) {
        mWebViewCore.setMockDeviceOrientation(canProvideAlpha, alpha, canProvideBeta, beta,
                canProvideGamma, gamma);
    }

    // This is used to determine long press with the center key.  Does not
    // affect long press with the trackball/touch.
    private boolean mGotCenterDown = false;

    @Override
    public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) {
        if (mBlockWebkitViewMessages) {
            return false;
        }
        // send complex characters to webkit for use by JS and plugins
        if (keyCode == KeyEvent.KEYCODE_UNKNOWN && event.getCharacters() != null) {
            // pass the key to DOM
            mWebViewCore.sendMessage(EventHub.KEY_DOWN, event);
            mWebViewCore.sendMessage(EventHub.KEY_UP, event);
            // return true as DOM handles the key
            return true;
        }
        return false;
    }

    private boolean isEnterActionKey(int keyCode) {
        return keyCode == KeyEvent.KEYCODE_DPAD_CENTER
                || keyCode == KeyEvent.KEYCODE_ENTER
                || keyCode == KeyEvent.KEYCODE_NUMPAD_ENTER;
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "keyDown at " + System.currentTimeMillis()
                    + "keyCode=" + keyCode
                    + ", " + event + ", unicode=" + event.getUnicodeChar());
        }
        if (mBlockWebkitViewMessages) {
            return false;
        }

        // don't implement accelerator keys here; defer to host application
        if (event.isCtrlPressed()) {
            return false;
        }

        if (mNativeClass == 0) {
            return false;
        }

        // do this hack up front, so it always works, regardless of touch-mode
        if (AUTO_REDRAW_HACK && (keyCode == KeyEvent.KEYCODE_CALL)) {
            mAutoRedraw = !mAutoRedraw;
            if (mAutoRedraw) {
                invalidate();
            }
            return true;
        }

        // Bubble up the key event if
        // 1. it is a system key; or
        // 2. the host application wants to handle it;
        if (event.isSystem()
                || mCallbackProxy.uiOverrideKeyEvent(event)) {
            return false;
        }

        // accessibility support
        if (accessibilityScriptInjected()) {
            if (AccessibilityManager.getInstance(mContext).isEnabled()) {
                // if an accessibility script is injected we delegate to it the key handling.
                // this script is a screen reader which is a fully fledged solution for blind
                // users to navigate in and interact with web pages.
                mWebViewCore.sendMessage(EventHub.KEY_DOWN, event);
                return true;
            } else {
                // Clean up if accessibility was disabled after loading the current URL.
                mAccessibilityScriptInjected = false;
            }
        } else if (mAccessibilityInjector != null) {
            if (AccessibilityManager.getInstance(mContext).isEnabled()) {
                if (mAccessibilityInjector.onKeyEvent(event)) {
                    // if an accessibility injector is present (no JavaScript enabled or the site
                    // opts out injecting our JavaScript screen reader) we let it decide whether
                    // to act on and consume the event.
                    return true;
                }
            } else {
                // Clean up if accessibility was disabled after loading the current URL.
                mAccessibilityInjector = null;
            }
        }

        if (keyCode == KeyEvent.KEYCODE_PAGE_UP) {
            if (event.hasNoModifiers()) {
                pageUp(false);
                return true;
            } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) {
                pageUp(true);
                return true;
            }
        }

        if (keyCode == KeyEvent.KEYCODE_PAGE_DOWN) {
            if (event.hasNoModifiers()) {
                pageDown(false);
                return true;
            } else if (event.hasModifiers(KeyEvent.META_ALT_ON)) {
                pageDown(true);
                return true;
            }
        }

        if (keyCode == KeyEvent.KEYCODE_MOVE_HOME && event.hasNoModifiers()) {
            pageUp(true);
            return true;
        }

        if (keyCode == KeyEvent.KEYCODE_MOVE_END && event.hasNoModifiers()) {
            pageDown(true);
            return true;
        }

        if (keyCode >= KeyEvent.KEYCODE_DPAD_UP
                && keyCode <= KeyEvent.KEYCODE_DPAD_RIGHT) {
            switchOutDrawHistory();
            if (nativePageShouldHandleShiftAndArrows()) {
                letPageHandleNavKey(keyCode, event.getEventTime(), true, event.getMetaState());
                return true;
            }
            if (event.hasModifiers(KeyEvent.META_ALT_ON)) {
                switch (keyCode) {
                    case KeyEvent.KEYCODE_DPAD_UP:
                        pageUp(true);
                        return true;
                    case KeyEvent.KEYCODE_DPAD_DOWN:
                        pageDown(true);
                        return true;
                    case KeyEvent.KEYCODE_DPAD_LEFT:
                        nativeClearCursor(); // start next trackball movement from page edge
                        return pinScrollTo(0, mScrollY, true, 0);
                    case KeyEvent.KEYCODE_DPAD_RIGHT:
                        nativeClearCursor(); // start next trackball movement from page edge
                        return pinScrollTo(mContentWidth, mScrollY, true, 0);
                }
            }
            if (navHandledKey(keyCode, 1, false, event.getEventTime())) {
                playSoundEffect(keyCodeToSoundsEffect(keyCode));
                return true;
            }
            // Bubble up the key event as WebView doesn't handle it
            return false;
        }

        if (isEnterActionKey(keyCode)) {
            switchOutDrawHistory();
            boolean wantsKeyEvents = nativeCursorNodePointer() == 0
                || nativeCursorWantsKeyEvents();
            if (event.getRepeatCount() == 0) {
                if (mSelectingText) {
                    return true; // discard press if copy in progress
                }
                mGotCenterDown = true;
                mPrivateHandler.sendMessageDelayed(mPrivateHandler
                        .obtainMessage(LONG_PRESS_CENTER), LONG_PRESS_TIMEOUT);
                if (!wantsKeyEvents) return true;
            }
            // Bubble up the key event as WebView doesn't handle it
            if (!wantsKeyEvents) return false;
        }

        if (getSettings().getNavDump()) {
            switch (keyCode) {
                case KeyEvent.KEYCODE_4:
                    dumpDisplayTree();
                    break;
                case KeyEvent.KEYCODE_5:
                case KeyEvent.KEYCODE_6:
                    dumpDomTree(keyCode == KeyEvent.KEYCODE_5);
                    break;
                case KeyEvent.KEYCODE_7:
                case KeyEvent.KEYCODE_8:
                    dumpRenderTree(keyCode == KeyEvent.KEYCODE_7);
                    break;
            }
        }

        if (nativeCursorIsTextInput()) {
            // This message will put the node in focus, for the DOM's notion
            // of focus.
            mWebViewCore.sendMessage(EventHub.FAKE_CLICK, nativeCursorFramePointer(),
                    nativeCursorNodePointer());
            // This will bring up the WebTextView and put it in focus, for
            // our view system's notion of focus
            rebuildWebTextView();
            // Now we need to pass the event to it
            if (inEditingMode()) {
                mWebTextView.setDefaultSelection();
                return mWebTextView.dispatchKeyEvent(event);
            }
        } else if (nativeHasFocusNode()) {
            // In this case, the cursor is not on a text input, but the focus
            // might be.  Check it, and if so, hand over to the WebTextView.
            rebuildWebTextView();
            if (inEditingMode()) {
                mWebTextView.setDefaultSelection();
                return mWebTextView.dispatchKeyEvent(event);
            }
        }

        // TODO: should we pass all the keys to DOM or check the meta tag
        if (nativeCursorWantsKeyEvents() || true) {
            // pass the key to DOM
            mWebViewCore.sendMessage(EventHub.KEY_DOWN, event);
            // return true as DOM handles the key
            return true;
        }

        // Bubble up the key event as WebView doesn't handle it
        return false;
    }

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "keyUp at " + System.currentTimeMillis()
                    + ", " + event + ", unicode=" + event.getUnicodeChar());
        }
        if (mBlockWebkitViewMessages) {
            return false;
        }

        if (mNativeClass == 0) {
            return false;
        }

        // special CALL handling when cursor node's href is "tel:XXX"
        if (keyCode == KeyEvent.KEYCODE_CALL && nativeHasCursorNode()) {
            String text = nativeCursorText();
            if (!nativeCursorIsTextInput() && text != null
                    && text.startsWith(SCHEME_TEL)) {
                Intent intent = new Intent(Intent.ACTION_DIAL, Uri.parse(text));
                getContext().startActivity(intent);
                return true;
            }
        }

        // Bubble up the key event if
        // 1. it is a system key; or
        // 2. the host application wants to handle it;
        if (event.isSystem()
                || mCallbackProxy.uiOverrideKeyEvent(event)) {
            return false;
        }

        // accessibility support
        if (accessibilityScriptInjected()) {
            if (AccessibilityManager.getInstance(mContext).isEnabled()) {
                // if an accessibility script is injected we delegate to it the key handling.
                // this script is a screen reader which is a fully fledged solution for blind
                // users to navigate in and interact with web pages.
                mWebViewCore.sendMessage(EventHub.KEY_UP, event);
                return true;
            } else {
                // Clean up if accessibility was disabled after loading the current URL.
                mAccessibilityScriptInjected = false;
            }
        } else if (mAccessibilityInjector != null) {
            if (AccessibilityManager.getInstance(mContext).isEnabled()) {
                if (mAccessibilityInjector.onKeyEvent(event)) {
                    // if an accessibility injector is present (no JavaScript enabled or the site
                    // opts out injecting our JavaScript screen reader) we let it decide whether to
                    // act on and consume the event.
                    return true;
                }
            } else {
                // Clean up if accessibility was disabled after loading the current URL.
                mAccessibilityInjector = null;
            }
        }

        if (keyCode >= KeyEvent.KEYCODE_DPAD_UP
                && keyCode <= KeyEvent.KEYCODE_DPAD_RIGHT) {
            if (nativePageShouldHandleShiftAndArrows()) {
                letPageHandleNavKey(keyCode, event.getEventTime(), false, event.getMetaState());
                return true;
            }
            // always handle the navigation keys in the UI thread
            // Bubble up the key event as WebView doesn't handle it
            return false;
        }

        if (isEnterActionKey(keyCode)) {
            // remove the long press message first
            mPrivateHandler.removeMessages(LONG_PRESS_CENTER);
            mGotCenterDown = false;

            if (mSelectingText) {
                copySelection();
                selectionDone();
                return true; // discard press if copy in progress
            }

            if (!sDisableNavcache) {
                // perform the single click
                Rect visibleRect = sendOurVisibleRect();
                // Note that sendOurVisibleRect calls viewToContent, so the
                // coordinates should be in content coordinates.
                if (!nativeCursorIntersects(visibleRect)) {
                    return false;
                }
                WebViewCore.CursorData data = cursorData();
                mWebViewCore.sendMessage(EventHub.SET_MOVE_MOUSE, data);
                playSoundEffect(SoundEffectConstants.CLICK);
                if (nativeCursorIsTextInput()) {
                    rebuildWebTextView();
                    centerKeyPressOnTextField();
                    if (inEditingMode()) {
                        mWebTextView.setDefaultSelection();
                    }
                    return true;
                }
                clearTextEntry();
                nativeShowCursorTimed();
                if (mCallbackProxy.uiOverrideUrlLoading(nativeCursorText())) {
                    return true;
                }
                if (nativeCursorNodePointer() != 0 && !nativeCursorWantsKeyEvents()) {
                    mWebViewCore.sendMessage(EventHub.CLICK, data.mFrame,
                            nativeCursorNodePointer());
                    return true;
                }
            }
        }

        // TODO: should we pass all the keys to DOM or check the meta tag
        if (nativeCursorWantsKeyEvents() || true) {
            // pass the key to DOM
            mWebViewCore.sendMessage(EventHub.KEY_UP, event);
            // return true as DOM handles the key
            return true;
        }

        // Bubble up the key event as WebView doesn't handle it
        return false;
    }

    private boolean startSelectActionMode() {
        mSelectCallback = new SelectActionModeCallback();
        mSelectCallback.setWebView(this);
        if (startActionMode(mSelectCallback) == null) {
            // There is no ActionMode, so do not allow the user to modify a
            // selection.
            selectionDone();
            return false;
        }
        performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
        return true;
    }

    private void syncSelectionCursors() {
        mSelectCursorBaseLayerId =
                nativeGetHandleLayerId(mNativeClass, HANDLE_ID_BASE, mSelectCursorBase);
        mSelectCursorExtentLayerId =
                nativeGetHandleLayerId(mNativeClass, HANDLE_ID_EXTENT, mSelectCursorExtent);
    }

    private boolean setupWebkitSelect() {
        syncSelectionCursors();
        if (!startSelectActionMode()) {
            selectionDone();
            return false;
        }
        mSelectingText = true;
        mTouchMode = TOUCH_DRAG_MODE;
        return true;
    }

    private void updateWebkitSelection() {
        int[] handles = null;
        if (mSelectingText) {
            handles = new int[4];
            handles[0] = mSelectCursorBase.centerX();
            handles[1] = mSelectCursorBase.centerY();
            handles[2] = mSelectCursorExtent.centerX();
            handles[3] = mSelectCursorExtent.centerY();
        } else {
            nativeSetTextSelection(mNativeClass, 0);
        }
        mWebViewCore.removeMessages(EventHub.SELECT_TEXT);
        mWebViewCore.sendMessageAtFrontOfQueue(EventHub.SELECT_TEXT, handles);
    }

    /**
     * Use this method to put the WebView into text selection mode.
     * Do not rely on this functionality; it will be deprecated in the future.
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public void emulateShiftHeld() {
        checkThread();
    }

    /**
     * Select all of the text in this WebView.
     *
     * @hide This is an implementation detail.
     */
    public void selectAll() {
        mWebViewCore.sendMessage(EventHub.SELECT_ALL);
    }

    /**
     * Called when the selection has been removed.
     */
    void selectionDone() {
        if (mSelectingText) {
            mSelectingText = false;
            // finish is idempotent, so this is fine even if selectionDone was
            // called by mSelectCallback.onDestroyActionMode
            mSelectCallback.finish();
            mSelectCallback = null;
            updateWebkitSelection();
            invalidate(); // redraw without selection
            mAutoScrollX = 0;
            mAutoScrollY = 0;
            mSentAutoScrollMessage = false;
        }
    }

    /**
     * Copy the selection to the clipboard
     *
     * @hide This is an implementation detail.
     */
    public boolean copySelection() {
        boolean copiedSomething = false;
        String selection = getSelection();
        if (selection != null && selection != "") {
            if (DebugFlags.WEB_VIEW) {
                Log.v(LOGTAG, "copySelection \"" + selection + "\"");
            }
            Toast.makeText(mContext
                    , com.android.internal.R.string.text_copied
                    , Toast.LENGTH_SHORT).show();
            copiedSomething = true;
            ClipboardManager cm = (ClipboardManager)getContext()
                    .getSystemService(Context.CLIPBOARD_SERVICE);
            cm.setText(selection);
            int[] handles = new int[4];
            getSelectionHandles(handles);
            mWebViewCore.sendMessage(EventHub.COPY_TEXT, handles);
        }
        invalidate(); // remove selection region and pointer
        return copiedSomething;
    }

    /**
     * Cut the selected text into the clipboard
     *
     * @hide This is an implementation detail
     */
    public void cutSelection() {
        copySelection();
        int[] handles = new int[4];
        getSelectionHandles(handles);
        mWebViewCore.sendMessage(EventHub.DELETE_TEXT, handles);
    }

    /**
     * Paste text from the clipboard to the cursor position.
     *
     * @hide This is an implementation detail
     */
    public void pasteFromClipboard() {
        ClipboardManager cm = (ClipboardManager)getContext()
                .getSystemService(Context.CLIPBOARD_SERVICE);
        ClipData clipData = cm.getPrimaryClip();
        if (clipData != null) {
            ClipData.Item clipItem = clipData.getItemAt(0);
            CharSequence pasteText = clipItem.getText();
            if (pasteText != null) {
                int[] handles = new int[4];
                getSelectionHandles(handles);
                mWebViewCore.sendMessage(EventHub.DELETE_TEXT, handles);
                mWebViewCore.sendMessage(EventHub.INSERT_TEXT,
                        pasteText.toString());
            }
        }
    }

    /**
     * @hide This is an implementation detail.
     */
    public SearchBox getSearchBox() {
        if ((mWebViewCore == null) || (mWebViewCore.getBrowserFrame() == null)) {
            return null;
        }
        return mWebViewCore.getBrowserFrame().getSearchBox();
    }

    /**
     * Returns the currently highlighted text as a string.
     */
    String getSelection() {
        if (mNativeClass == 0) return "";
        return nativeGetSelection();
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        if (hasWindowFocus()) setActive(true);
        final ViewTreeObserver treeObserver = getViewTreeObserver();
        if (mGlobalLayoutListener == null) {
            mGlobalLayoutListener = new InnerGlobalLayoutListener();
            treeObserver.addOnGlobalLayoutListener(mGlobalLayoutListener);
        }
        if (mScrollChangedListener == null) {
            mScrollChangedListener = new InnerScrollChangedListener();
            treeObserver.addOnScrollChangedListener(mScrollChangedListener);
        }

        addAccessibilityApisToJavaScript();

        mTouchEventQueue.reset();
    }

    @Override
    protected void onDetachedFromWindow() {
        clearHelpers();
        mZoomManager.dismissZoomPicker();
        if (hasWindowFocus()) setActive(false);

        final ViewTreeObserver treeObserver = getViewTreeObserver();
        if (mGlobalLayoutListener != null) {
            treeObserver.removeGlobalOnLayoutListener(mGlobalLayoutListener);
            mGlobalLayoutListener = null;
        }
        if (mScrollChangedListener != null) {
            treeObserver.removeOnScrollChangedListener(mScrollChangedListener);
            mScrollChangedListener = null;
        }

        removeAccessibilityApisFromJavaScript();

        super.onDetachedFromWindow();
    }

    @Override
    protected void onVisibilityChanged(View changedView, int visibility) {
        super.onVisibilityChanged(changedView, visibility);
        // The zoomManager may be null if the webview is created from XML that
        // specifies the view's visibility param as not visible (see http://b/2794841)
        if (visibility != View.VISIBLE && mZoomManager != null) {
            mZoomManager.dismissZoomPicker();
        }
        updateDrawingState();
    }

    /**
     * @deprecated WebView no longer needs to implement
     * ViewGroup.OnHierarchyChangeListener.  This method does nothing now.
     */
    @Override
    // Cannot add @hide as this can always be accessed via the interface.
    @Deprecated
    public void onChildViewAdded(View parent, View child) {}

    /**
     * @deprecated WebView no longer needs to implement
     * ViewGroup.OnHierarchyChangeListener.  This method does nothing now.
     */
    @Override
    // Cannot add @hide as this can always be accessed via the interface.
    @Deprecated
    public void onChildViewRemoved(View p, View child) {}

    /**
     * @deprecated WebView should not have implemented
     * ViewTreeObserver.OnGlobalFocusChangeListener. This method does nothing now.
     */
    @Override
    // Cannot add @hide as this can always be accessed via the interface.
    @Deprecated
    public void onGlobalFocusChanged(View oldFocus, View newFocus) {
    }

    void setActive(boolean active) {
        if (active) {
            if (hasFocus()) {
                // If our window regained focus, and we have focus, then begin
                // drawing the cursor ring
                mDrawCursorRing = !inEditingMode();
                setFocusControllerActive(true);
            } else {
                mDrawCursorRing = false;
                if (!inEditingMode()) {
                    // If our window gained focus, but we do not have it, do not
                    // draw the cursor ring.
                    setFocusControllerActive(false);
                }
                // We do not call recordButtons here because we assume
                // that when we lost focus, or window focus, it got called with
                // false for the first parameter
            }
        } else {
            if (!mZoomManager.isZoomPickerVisible()) {
                /*
                 * The external zoom controls come in their own window, so our
                 * window loses focus. Our policy is to not draw the cursor ring
                 * if our window is not focused, but this is an exception since
                 * the user can still navigate the web page with the zoom
                 * controls showing.
                 */
                mDrawCursorRing = false;
            }
            mKeysPressed.clear();
            mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);
            mTouchMode = TOUCH_DONE_MODE;
            setFocusControllerActive(false);
        }
        invalidate();
    }

    // To avoid drawing the cursor ring, and remove the TextView when our window
    // loses focus.
    @Override
    public void onWindowFocusChanged(boolean hasWindowFocus) {
        setActive(hasWindowFocus);
        if (hasWindowFocus) {
            JWebCoreJavaBridge.setActiveWebView(this);
            if (mPictureUpdatePausedForFocusChange) {
                WebViewCore.resumeUpdatePicture(mWebViewCore);
                mPictureUpdatePausedForFocusChange = false;
            }
        } else {
            JWebCoreJavaBridge.removeActiveWebView(this);
            final WebSettings settings = getSettings();
            if (settings != null && settings.enableSmoothTransition() &&
                    mWebViewCore != null && !WebViewCore.isUpdatePicturePaused(mWebViewCore)) {
                WebViewCore.pauseUpdatePicture(mWebViewCore);
                mPictureUpdatePausedForFocusChange = true;
            }
        }
        super.onWindowFocusChanged(hasWindowFocus);
    }

    /*
     * Pass a message to WebCore Thread, telling the WebCore::Page's
     * FocusController to be  "inactive" so that it will
     * not draw the blinking cursor.  It gets set to "active" to draw the cursor
     * in WebViewCore.cpp, when the WebCore thread receives key events/clicks.
     */
    /* package */ void setFocusControllerActive(boolean active) {
        if (mWebViewCore == null) return;
        mWebViewCore.sendMessage(EventHub.SET_ACTIVE, active ? 1 : 0, 0);
        // Need to send this message after the document regains focus.
        if (active && mListBoxMessage != null) {
            mWebViewCore.sendMessage(mListBoxMessage);
            mListBoxMessage = null;
        }
    }

    @Override
    protected void onFocusChanged(boolean focused, int direction,
            Rect previouslyFocusedRect) {
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "MT focusChanged " + focused + ", " + direction);
        }
        if (focused) {
            // When we regain focus, if we have window focus, resume drawing
            // the cursor ring
            if (hasWindowFocus()) {
                mDrawCursorRing = !inEditingMode();
                setFocusControllerActive(true);
            //} else {
                // The WebView has gained focus while we do not have
                // windowfocus.  When our window lost focus, we should have
                // called recordButtons(false...)
            }
        } else {
            // When we lost focus, unless focus went to the TextView (which is
            // true if we are in editing mode), stop drawing the cursor ring.
            mDrawCursorRing = false;
            if (!inEditingMode()) {
                setFocusControllerActive(false);
            }
            mKeysPressed.clear();
        }

        super.onFocusChanged(focused, direction, previouslyFocusedRect);
    }

    void setGLRectViewport() {
        // Use the getGlobalVisibleRect() to get the intersection among the parents
        // visible == false means we're clipped - send a null rect down to indicate that
        // we should not draw
        boolean visible = getGlobalVisibleRect(mGLRectViewport);
        if (visible) {
            // Then need to invert the Y axis, just for GL
            View rootView = getRootView();
            int rootViewHeight = rootView.getHeight();
            mViewRectViewport.set(mGLRectViewport);
            int savedWebViewBottom = mGLRectViewport.bottom;
            mGLRectViewport.bottom = rootViewHeight - mGLRectViewport.top - getVisibleTitleHeightImpl();
            mGLRectViewport.top = rootViewHeight - savedWebViewBottom;
            mGLViewportEmpty = false;
        } else {
            mGLViewportEmpty = true;
        }
        calcOurContentVisibleRectF(mVisibleContentRect);
        nativeUpdateDrawGLFunction(mGLViewportEmpty ? null : mGLRectViewport,
                mGLViewportEmpty ? null : mViewRectViewport,
                mVisibleContentRect, getScale());
    }

    /**
     * @hide
     */
    @Override
    protected boolean setFrame(int left, int top, int right, int bottom) {
        boolean changed = super.setFrame(left, top, right, bottom);
        if (!changed && mHeightCanMeasure) {
            // When mHeightCanMeasure is true, we will set mLastHeightSent to 0
            // in WebViewCore after we get the first layout. We do call
            // requestLayout() when we get contentSizeChanged(). But the View
            // system won't call onSizeChanged if the dimension is not changed.
            // In this case, we need to call sendViewSizeZoom() explicitly to
            // notify the WebKit about the new dimensions.
            sendViewSizeZoom(false);
        }
        setGLRectViewport();
        return changed;
    }

    @Override
    protected void onSizeChanged(int w, int h, int ow, int oh) {
        super.onSizeChanged(w, h, ow, oh);

        // adjust the max viewport width depending on the view dimensions. This
        // is to ensure the scaling is not going insane. So do not shrink it if
        // the view size is temporarily smaller, e.g. when soft keyboard is up.
        int newMaxViewportWidth = (int) (Math.max(w, h) / mZoomManager.getDefaultMinZoomScale());
        if (newMaxViewportWidth > sMaxViewportWidth) {
            sMaxViewportWidth = newMaxViewportWidth;
        }

        mZoomManager.onSizeChanged(w, h, ow, oh);

        if (mLoadedPicture != null && mDelaySetPicture == null) {
            // Size changes normally result in a new picture
            // Re-set the loaded picture to simulate that
            // However, do not update the base layer as that hasn't changed
            setNewPicture(mLoadedPicture, false);
        }
    }

    @Override
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        super.onScrollChanged(l, t, oldl, oldt);
        if (!mInOverScrollMode) {
            sendOurVisibleRect();
            // update WebKit if visible title bar height changed. The logic is same
            // as getVisibleTitleHeightImpl.
            int titleHeight = getTitleHeight();
            if (Math.max(titleHeight - t, 0) != Math.max(titleHeight - oldt, 0)) {
                sendViewSizeZoom(false);
            }
        }
    }

    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        switch (event.getAction()) {
            case KeyEvent.ACTION_DOWN:
                mKeysPressed.add(Integer.valueOf(event.getKeyCode()));
                break;
            case KeyEvent.ACTION_MULTIPLE:
                // Always accept the action.
                break;
            case KeyEvent.ACTION_UP:
                int location = mKeysPressed.indexOf(Integer.valueOf(event.getKeyCode()));
                if (location == -1) {
                    // We did not receive the key down for this key, so do not
                    // handle the key up.
                    return false;
                } else {
                    // We did receive the key down.  Handle the key up, and
                    // remove it from our pressed keys.
                    mKeysPressed.remove(location);
                }
                break;
            default:
                // Accept the action.  This should not happen, unless a new
                // action is added to KeyEvent.
                break;
        }
        if (inEditingMode() && mWebTextView.isFocused()) {
            // Ensure that the WebTextView gets the event, even if it does
            // not currently have a bounds.
            return mWebTextView.dispatchKeyEvent(event);
        } else {
            return super.dispatchKeyEvent(event);
        }
    }

    /*
     * Here is the snap align logic:
     * 1. If it starts nearly horizontally or vertically, snap align;
     * 2. If there is a dramitic direction change, let it go;
     *
     * Adjustable parameters. Angle is the radians on a unit circle, limited
     * to quadrant 1. Values range from 0f (horizontal) to PI/2 (vertical)
     */
    private static final float HSLOPE_TO_START_SNAP = .25f;
    private static final float HSLOPE_TO_BREAK_SNAP = .4f;
    private static final float VSLOPE_TO_START_SNAP = 1.25f;
    private static final float VSLOPE_TO_BREAK_SNAP = .95f;
    /*
     *  These values are used to influence the average angle when entering
     *  snap mode. If is is the first movement entering snap, we set the average
     *  to the appropriate ideal. If the user is entering into snap after the
     *  first movement, then we average the average angle with these values.
     */
    private static final float ANGLE_VERT = 2f;
    private static final float ANGLE_HORIZ = 0f;
    /*
     *  The modified moving average weight.
     *  Formula: MAV[t]=MAV[t-1] + (P[t]-MAV[t-1])/n
     */
    private static final float MMA_WEIGHT_N = 5;

    private boolean hitFocusedPlugin(int contentX, int contentY) {
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "nativeFocusIsPlugin()=" + nativeFocusIsPlugin());
            Rect r = nativeFocusNodeBounds();
            Log.v(LOGTAG, "nativeFocusNodeBounds()=(" + r.left + ", " + r.top
                    + ", " + r.right + ", " + r.bottom + ")");
        }
        return nativeFocusIsPlugin()
                && nativeFocusNodeBounds().contains(contentX, contentY);
    }

    private boolean shouldForwardTouchEvent() {
        if (mFullScreenHolder != null) return true;
        if (mBlockWebkitViewMessages) return false;
        return mForwardTouchEvents
                && !mSelectingText
                && mPreventDefault != PREVENT_DEFAULT_IGNORE
                && mPreventDefault != PREVENT_DEFAULT_NO;
    }

    private boolean inFullScreenMode() {
        return mFullScreenHolder != null;
    }

    private void dismissFullScreenMode() {
        if (inFullScreenMode()) {
            mFullScreenHolder.hide();
            mFullScreenHolder = null;
            invalidate();
        }
    }

    void onPinchToZoomAnimationStart() {
        // cancel the single touch handling
        cancelTouch();
        onZoomAnimationStart();
    }

    void onPinchToZoomAnimationEnd(ScaleGestureDetector detector) {
        onZoomAnimationEnd();
        // start a drag, TOUCH_PINCH_DRAG, can't use TOUCH_INIT_MODE as
        // it may trigger the unwanted click, can't use TOUCH_DRAG_MODE
        // as it may trigger the unwanted fling.
        mTouchMode = TOUCH_PINCH_DRAG;
        mConfirmMove = true;
        startTouch(detector.getFocusX(), detector.getFocusY(), mLastTouchTime);
    }

    // See if there is a layer at x, y and switch to TOUCH_DRAG_LAYER_MODE if a
    // layer is found.
    private void startScrollingLayer(float x, float y) {
        int contentX = viewToContentX((int) x + mScrollX);
        int contentY = viewToContentY((int) y + mScrollY);
        mCurrentScrollingLayerId = nativeScrollableLayer(contentX, contentY,
                mScrollingLayerRect, mScrollingLayerBounds);
        if (mCurrentScrollingLayerId != 0) {
            mTouchMode = TOUCH_DRAG_LAYER_MODE;
        }
    }

    // 1/(density * density) used to compute the distance between points.
    // Computed in init().
    private float DRAG_LAYER_INVERSE_DENSITY_SQUARED;

    // The distance between two points reported in onTouchEvent scaled by the
    // density of the screen.
    private static final int DRAG_LAYER_FINGER_DISTANCE = 20000;

    @Override
    public boolean onHoverEvent(MotionEvent event) {
        if (mNativeClass == 0) {
            return false;
        }
        WebViewCore.CursorData data = cursorDataNoPosition();
        data.mX = viewToContentX((int) event.getX() + mScrollX);
        data.mY = viewToContentY((int) event.getY() + mScrollY);
        mWebViewCore.sendMessage(EventHub.SET_MOVE_MOUSE, data);
        return true;
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if (mNativeClass == 0 || (!isClickable() && !isLongClickable())) {
            return false;
        }

        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, ev + " at " + ev.getEventTime()
                + " mTouchMode=" + mTouchMode
                + " numPointers=" + ev.getPointerCount());
        }

        // If WebKit wasn't interested in this multitouch gesture, enqueue
        // the event for handling directly rather than making the round trip
        // to WebKit and back.
        if (ev.getPointerCount() > 1 && mPreventDefault != PREVENT_DEFAULT_NO) {
            passMultiTouchToWebKit(ev, mTouchEventQueue.nextTouchSequence());
        } else {
            mTouchEventQueue.enqueueTouchEvent(ev);
        }

        // Since all events are handled asynchronously, we always want the gesture stream.
        return true;
    }

    private float calculateDragAngle(int dx, int dy) {
        dx = Math.abs(dx);
        dy = Math.abs(dy);
        return (float) Math.atan2(dy, dx);
    }

    /*
     * Common code for single touch and multi-touch.
     * (x, y) denotes current focus point, which is the touch point for single touch
     * and the middle point for multi-touch.
     */
    private boolean handleTouchEventCommon(MotionEvent ev, int action, int x, int y) {
        long eventTime = ev.getEventTime();

        // Due to the touch screen edge effect, a touch closer to the edge
        // always snapped to the edge. As getViewWidth() can be different from
        // getWidth() due to the scrollbar, adjusting the point to match
        // getViewWidth(). Same applied to the height.
        x = Math.min(x, getViewWidth() - 1);
        y = Math.min(y, getViewHeightWithTitle() - 1);

        int deltaX = mLastTouchX - x;
        int deltaY = mLastTouchY - y;
        int contentX = viewToContentX(x + mScrollX);
        int contentY = viewToContentY(y + mScrollY);

        switch (action) {
            case MotionEvent.ACTION_DOWN: {
                mPreventDefault = PREVENT_DEFAULT_NO;
                mConfirmMove = false;
                mInitialHitTestResult = null;
                if (!mScroller.isFinished()) {
                    // stop the current scroll animation, but if this is
                    // the start of a fling, allow it to add to the current
                    // fling's velocity
                    mScroller.abortAnimation();
                    mTouchMode = TOUCH_DRAG_START_MODE;
                    mConfirmMove = true;
                    nativeSetIsScrolling(false);
                } else if (mPrivateHandler.hasMessages(RELEASE_SINGLE_TAP)) {
                    mPrivateHandler.removeMessages(RELEASE_SINGLE_TAP);
                    if (sDisableNavcache) {
                        removeTouchHighlight();
                    }
                    if (deltaX * deltaX + deltaY * deltaY < mDoubleTapSlopSquare) {
                        mTouchMode = TOUCH_DOUBLE_TAP_MODE;
                    } else {
                        // commit the short press action for the previous tap
                        doShortPress();
                        mTouchMode = TOUCH_INIT_MODE;
                        mDeferTouchProcess = !mBlockWebkitViewMessages
                                && (!inFullScreenMode() && mForwardTouchEvents)
                                ? hitFocusedPlugin(contentX, contentY)
                                : false;
                    }
                } else { // the normal case
                    mTouchMode = TOUCH_INIT_MODE;
                    mDeferTouchProcess = !mBlockWebkitViewMessages
                            && (!inFullScreenMode() && mForwardTouchEvents)
                            ? hitFocusedPlugin(contentX, contentY)
                            : false;
                    if (!mBlockWebkitViewMessages) {
                        mWebViewCore.sendMessage(
                                EventHub.UPDATE_FRAME_CACHE_IF_LOADING);
                    }
                    if (sDisableNavcache) {
                        TouchHighlightData data = new TouchHighlightData();
                        data.mX = contentX;
                        data.mY = contentY;
                        data.mNativeLayerRect = new Rect();
                        data.mNativeLayer = nativeScrollableLayer(
                                contentX, contentY, data.mNativeLayerRect, null);
                        data.mSlop = viewToContentDimension(mNavSlop);
                        mTouchHighlightRegion.setEmpty();
                        if (!mBlockWebkitViewMessages) {
                            mTouchHighlightRequested = System.currentTimeMillis();
                            mWebViewCore.sendMessageAtFrontOfQueue(
                                    EventHub.HIT_TEST, data);
                        }
                        if (DEBUG_TOUCH_HIGHLIGHT) {
                            if (getSettings().getNavDump()) {
                                mTouchHighlightX = x + mScrollX;
                                mTouchHighlightY = y + mScrollY;
                                mPrivateHandler.postDelayed(new Runnable() {
                                    @Override
                                    public void run() {
                                        mTouchHighlightX = mTouchHighlightY = 0;
                                        invalidate();
                                    }
                                }, TOUCH_HIGHLIGHT_ELAPSE_TIME);
                            }
                        }
                    }
                    if (mLogEvent && eventTime - mLastTouchUpTime < 1000) {
                        EventLog.writeEvent(EventLogTags.BROWSER_DOUBLE_TAP_DURATION,
                                (eventTime - mLastTouchUpTime), eventTime);
                    }
                    mSelectionStarted = false;
                    if (mSelectingText && mSelectHandleLeft != null
                            && mSelectHandleRight != null) {
                        int shiftedY = y - getTitleHeight() + mScrollY;
                        int shiftedX = x + mScrollX;
                        if (mSelectHandleLeft.getBounds()
                                .contains(shiftedX, shiftedY)) {
                            mSelectionStarted = true;
                            mSelectDraggingCursor = mSelectCursorBase;
                        } else if (mSelectHandleRight.getBounds()
                                .contains(shiftedX, shiftedY)) {
                            mSelectionStarted = true;
                            mSelectDraggingCursor = mSelectCursorExtent;
                        }
                        if (mSelectDraggingCursor != null) {
                            mSelectDraggingOffset.set(
                                    mSelectDraggingCursor.left - contentX,
                                    mSelectDraggingCursor.top - contentY);
                        }
                        if (DebugFlags.WEB_VIEW) {
                            Log.v(LOGTAG, "select=" + contentX + "," + contentY);
                        }
                    }
                }
                // Trigger the link
                if (!mSelectingText && (mTouchMode == TOUCH_INIT_MODE
                        || mTouchMode == TOUCH_DOUBLE_TAP_MODE)) {
                    mPrivateHandler.sendEmptyMessageDelayed(
                            SWITCH_TO_SHORTPRESS, TAP_TIMEOUT);
                    mPrivateHandler.sendEmptyMessageDelayed(
                            SWITCH_TO_LONGPRESS, LONG_PRESS_TIMEOUT);
                    if (inFullScreenMode() || mDeferTouchProcess) {
                        mPreventDefault = PREVENT_DEFAULT_YES;
                    } else if (!mBlockWebkitViewMessages && mForwardTouchEvents) {
                        mPreventDefault = PREVENT_DEFAULT_MAYBE_YES;
                    } else {
                        mPreventDefault = PREVENT_DEFAULT_NO;
                    }
                    // pass the touch events from UI thread to WebCore thread
                    if (shouldForwardTouchEvent()) {
                        TouchEventData ted = new TouchEventData();
                        ted.mAction = action;
                        ted.mIds = new int[1];
                        ted.mIds[0] = ev.getPointerId(0);
                        ted.mPoints = new Point[1];
                        ted.mPoints[0] = new Point(contentX, contentY);
                        ted.mPointsInView = new Point[1];
                        ted.mPointsInView[0] = new Point(x, y);
                        ted.mMetaState = ev.getMetaState();
                        ted.mReprocess = mDeferTouchProcess;
                        ted.mNativeLayer = nativeScrollableLayer(
                                contentX, contentY, ted.mNativeLayerRect, null);
                        ted.mSequence = mTouchEventQueue.nextTouchSequence();
                        mTouchEventQueue.preQueueTouchEventData(ted);
                        mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                        if (mDeferTouchProcess) {
                            // still needs to set them for compute deltaX/Y
                            mLastTouchX = x;
                            mLastTouchY = y;
                            break;
                        }
                        if (!inFullScreenMode()) {
                            mPrivateHandler.removeMessages(PREVENT_DEFAULT_TIMEOUT);
                            mPrivateHandler.sendMessageDelayed(mPrivateHandler
                                    .obtainMessage(PREVENT_DEFAULT_TIMEOUT,
                                            action, 0), TAP_TIMEOUT);
                        }
                    }
                }
                startTouch(x, y, eventTime);
                break;
            }
            case MotionEvent.ACTION_MOVE: {
                boolean firstMove = false;
                if (!mConfirmMove && (deltaX * deltaX + deltaY * deltaY)
                        >= mTouchSlopSquare) {
                    mPrivateHandler.removeMessages(SWITCH_TO_SHORTPRESS);
                    mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);
                    mConfirmMove = true;
                    firstMove = true;
                    if (mTouchMode == TOUCH_DOUBLE_TAP_MODE) {
                        mTouchMode = TOUCH_INIT_MODE;
                    }
                    if (sDisableNavcache) {
                        removeTouchHighlight();
                    }
                }
                if (mSelectingText && mSelectionStarted) {
                    if (DebugFlags.WEB_VIEW) {
                        Log.v(LOGTAG, "extend=" + contentX + "," + contentY);
                    }
                    ViewParent parent = getParent();
                    if (parent != null) {
                        parent.requestDisallowInterceptTouchEvent(true);
                    }
                    if (deltaX != 0 || deltaY != 0) {
                        mSelectDraggingCursor.offsetTo(
                                contentX + mSelectDraggingOffset.x,
                                contentY + mSelectDraggingOffset.y);
                        updateWebkitSelection();
                        mLastTouchX = x;
                        mLastTouchY = y;
                        invalidate();
                    }
                    break;
                }

                // pass the touch events from UI thread to WebCore thread
                if (shouldForwardTouchEvent() && mConfirmMove && (firstMove
                        || eventTime - mLastSentTouchTime > mCurrentTouchInterval)) {
                    TouchEventData ted = new TouchEventData();
                    ted.mAction = action;
                    ted.mIds = new int[1];
                    ted.mIds[0] = ev.getPointerId(0);
                    ted.mPoints = new Point[1];
                    ted.mPoints[0] = new Point(contentX, contentY);
                    ted.mPointsInView = new Point[1];
                    ted.mPointsInView[0] = new Point(x, y);
                    ted.mMetaState = ev.getMetaState();
                    ted.mReprocess = mDeferTouchProcess;
                    ted.mNativeLayer = mCurrentScrollingLayerId;
                    ted.mNativeLayerRect.set(mScrollingLayerRect);
                    ted.mSequence = mTouchEventQueue.nextTouchSequence();
                    mTouchEventQueue.preQueueTouchEventData(ted);
                    mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                    mLastSentTouchTime = eventTime;
                    if (mDeferTouchProcess) {
                        break;
                    }
                    if (firstMove && !inFullScreenMode()) {
                        mPrivateHandler.sendMessageDelayed(mPrivateHandler
                                .obtainMessage(PREVENT_DEFAULT_TIMEOUT,
                                        action, 0), TAP_TIMEOUT);
                    }
                }
                if (mTouchMode == TOUCH_DONE_MODE
                        || mPreventDefault == PREVENT_DEFAULT_YES) {
                    // no dragging during scroll zoom animation, or when prevent
                    // default is yes
                    break;
                }
                if (mVelocityTracker == null) {
                    Log.e(LOGTAG, "Got null mVelocityTracker when "
                            + "mPreventDefault = " + mPreventDefault
                            + " mDeferTouchProcess = " + mDeferTouchProcess
                            + " mTouchMode = " + mTouchMode);
                } else {
                    mVelocityTracker.addMovement(ev);
                }

                if (mTouchMode != TOUCH_DRAG_MODE &&
                        mTouchMode != TOUCH_DRAG_LAYER_MODE) {

                    if (!mConfirmMove) {
                        break;
                    }

                    if (mPreventDefault == PREVENT_DEFAULT_MAYBE_YES
                            || mPreventDefault == PREVENT_DEFAULT_NO_FROM_TOUCH_DOWN) {
                        // track mLastTouchTime as we may need to do fling at
                        // ACTION_UP
                        mLastTouchTime = eventTime;
                        break;
                    }

                    // Only lock dragging to one axis if we don't have a scale in progress.
                    // Scaling implies free-roaming movement. Note this is only ever a question
                    // if mZoomManager.supportsPanDuringZoom() is true.
                    final ScaleGestureDetector detector =
                      mZoomManager.getMultiTouchGestureDetector();
                    mAverageAngle = calculateDragAngle(deltaX, deltaY);
                    if (detector == null || !detector.isInProgress()) {
                        // if it starts nearly horizontal or vertical, enforce it
                        if (mAverageAngle < HSLOPE_TO_START_SNAP) {
                            mSnapScrollMode = SNAP_X;
                            mSnapPositive = deltaX > 0;
                            mAverageAngle = ANGLE_HORIZ;
                        } else if (mAverageAngle > VSLOPE_TO_START_SNAP) {
                            mSnapScrollMode = SNAP_Y;
                            mSnapPositive = deltaY > 0;
                            mAverageAngle = ANGLE_VERT;
                        }
                    }

                    mTouchMode = TOUCH_DRAG_MODE;
                    mLastTouchX = x;
                    mLastTouchY = y;
                    deltaX = 0;
                    deltaY = 0;

                    startScrollingLayer(x, y);
                    startDrag();
                }

                // do pan
                boolean done = false;
                boolean keepScrollBarsVisible = false;
                if (deltaX == 0 && deltaY == 0) {
                    keepScrollBarsVisible = done = true;
                } else {
                    mAverageAngle +=
                        (calculateDragAngle(deltaX, deltaY) - mAverageAngle)
                        / MMA_WEIGHT_N;
                    if (mSnapScrollMode != SNAP_NONE) {
                        if (mSnapScrollMode == SNAP_Y) {
                            // radical change means getting out of snap mode
                            if (mAverageAngle < VSLOPE_TO_BREAK_SNAP) {
                                mSnapScrollMode = SNAP_NONE;
                            }
                        }
                        if (mSnapScrollMode == SNAP_X) {
                            // radical change means getting out of snap mode
                            if (mAverageAngle > HSLOPE_TO_BREAK_SNAP) {
                                mSnapScrollMode = SNAP_NONE;
                            }
                        }
                    } else {
                        if (mAverageAngle < HSLOPE_TO_START_SNAP) {
                            mSnapScrollMode = SNAP_X;
                            mSnapPositive = deltaX > 0;
                            mAverageAngle = (mAverageAngle + ANGLE_HORIZ) / 2;
                        } else if (mAverageAngle > VSLOPE_TO_START_SNAP) {
                            mSnapScrollMode = SNAP_Y;
                            mSnapPositive = deltaY > 0;
                            mAverageAngle = (mAverageAngle + ANGLE_VERT) / 2;
                        }
                    }
                    if (mSnapScrollMode != SNAP_NONE) {
                        if ((mSnapScrollMode & SNAP_X) == SNAP_X) {
                            deltaY = 0;
                        } else {
                            deltaX = 0;
                        }
                    }
                    mLastTouchX = x;
                    mLastTouchY = y;

                    if (deltaX * deltaX + deltaY * deltaY > mTouchSlopSquare) {
                        mHeldMotionless = MOTIONLESS_FALSE;
                        nativeSetIsScrolling(true);
                    } else {
                        mHeldMotionless = MOTIONLESS_TRUE;
                        nativeSetIsScrolling(false);
                        keepScrollBarsVisible = true;
                    }

                    mLastTouchTime = eventTime;
                }

                doDrag(deltaX, deltaY);

                // Turn off scrollbars when dragging a layer.
                if (keepScrollBarsVisible &&
                        mTouchMode != TOUCH_DRAG_LAYER_MODE) {
                    if (mHeldMotionless != MOTIONLESS_TRUE) {
                        mHeldMotionless = MOTIONLESS_TRUE;
                        invalidate();
                    }
                    // keep the scrollbar on the screen even there is no scroll
                    awakenScrollBars(ViewConfiguration.getScrollDefaultDelay(),
                            false);
                    // Post a message so that we'll keep them alive while we're not scrolling.
                    mPrivateHandler.sendMessageDelayed(mPrivateHandler
                            .obtainMessage(AWAKEN_SCROLL_BARS),
                            ViewConfiguration.getScrollDefaultDelay());
                    // return false to indicate that we can't pan out of the
                    // view space
                    return !done;
                } else {
                    mPrivateHandler.removeMessages(AWAKEN_SCROLL_BARS);
                }
                break;
            }
            case MotionEvent.ACTION_UP: {
                if (!isFocused()) requestFocus();
                // pass the touch events from UI thread to WebCore thread
                if (shouldForwardTouchEvent()) {
                    TouchEventData ted = new TouchEventData();
                    ted.mIds = new int[1];
                    ted.mIds[0] = ev.getPointerId(0);
                    ted.mAction = action;
                    ted.mPoints = new Point[1];
                    ted.mPoints[0] = new Point(contentX, contentY);
                    ted.mPointsInView = new Point[1];
                    ted.mPointsInView[0] = new Point(x, y);
                    ted.mMetaState = ev.getMetaState();
                    ted.mReprocess = mDeferTouchProcess;
                    ted.mNativeLayer = mCurrentScrollingLayerId;
                    ted.mNativeLayerRect.set(mScrollingLayerRect);
                    ted.mSequence = mTouchEventQueue.nextTouchSequence();
                    mTouchEventQueue.preQueueTouchEventData(ted);
                    mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                }
                mLastTouchUpTime = eventTime;
                if (mSentAutoScrollMessage) {
                    mAutoScrollX = mAutoScrollY = 0;
                }
                switch (mTouchMode) {
                    case TOUCH_DOUBLE_TAP_MODE: // double tap
                        mPrivateHandler.removeMessages(SWITCH_TO_SHORTPRESS);
                        mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);
                        if (inFullScreenMode() || mDeferTouchProcess) {
                            TouchEventData ted = new TouchEventData();
                            ted.mIds = new int[1];
                            ted.mIds[0] = ev.getPointerId(0);
                            ted.mAction = WebViewCore.ACTION_DOUBLETAP;
                            ted.mPoints = new Point[1];
                            ted.mPoints[0] = new Point(contentX, contentY);
                            ted.mPointsInView = new Point[1];
                            ted.mPointsInView[0] = new Point(x, y);
                            ted.mMetaState = ev.getMetaState();
                            ted.mReprocess = mDeferTouchProcess;
                            ted.mNativeLayer = nativeScrollableLayer(
                                    contentX, contentY,
                                    ted.mNativeLayerRect, null);
                            ted.mSequence = mTouchEventQueue.nextTouchSequence();
                            mTouchEventQueue.preQueueTouchEventData(ted);
                            mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                        } else if (mPreventDefault != PREVENT_DEFAULT_YES){
                            mZoomManager.handleDoubleTap(mLastTouchX, mLastTouchY);
                            mTouchMode = TOUCH_DONE_MODE;
                        }
                        break;
                    case TOUCH_INIT_MODE: // tap
                    case TOUCH_SHORTPRESS_START_MODE:
                    case TOUCH_SHORTPRESS_MODE:
                        mPrivateHandler.removeMessages(SWITCH_TO_SHORTPRESS);
                        mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);
                        if (mConfirmMove) {
                            Log.w(LOGTAG, "Miss a drag as we are waiting for" +
                                    " WebCore's response for touch down.");
                            if (mPreventDefault != PREVENT_DEFAULT_YES
                                    && (computeMaxScrollX() > 0
                                            || computeMaxScrollY() > 0)) {
                                // If the user has performed a very quick touch
                                // sequence it is possible that we may get here
                                // before WebCore has had a chance to process the events.
                                // In this case, any call to preventDefault in the
                                // JS touch handler will not have been executed yet.
                                // Hence we will see both the UI (now) and WebCore
                                // (when context switches) handling the event,
                                // regardless of whether the web developer actually
                                // doeses preventDefault in their touch handler. This
                                // is the nature of our asynchronous touch model.

                                // we will not rewrite drag code here, but we
                                // will try fling if it applies.
                                WebViewCore.reducePriority();
                                // to get better performance, pause updating the
                                // picture
                                WebViewCore.pauseUpdatePicture(mWebViewCore);
                                // fall through to TOUCH_DRAG_MODE
                            } else {
                                // WebKit may consume the touch event and modify
                                // DOM. drawContentPicture() will be called with
                                // animateSroll as true for better performance.
                                // Force redraw in high-quality.
                                invalidate();
                                break;
                            }
                        } else {
                            if (mSelectingText) {
                                // tapping on selection or controls does nothing
                                if (!mSelectionStarted) {
                                    selectionDone();
                                }
                                break;
                            }
                            // only trigger double tap if the WebView is
                            // scalable
                            if (mTouchMode == TOUCH_INIT_MODE
                                    && (canZoomIn() || canZoomOut())) {
                                mPrivateHandler.sendEmptyMessageDelayed(
                                        RELEASE_SINGLE_TAP, ViewConfiguration
                                                .getDoubleTapTimeout());
                            } else {
                                doShortPress();
                            }
                            break;
                        }
                    case TOUCH_DRAG_MODE:
                    case TOUCH_DRAG_LAYER_MODE:
                        mPrivateHandler.removeMessages(DRAG_HELD_MOTIONLESS);
                        mPrivateHandler.removeMessages(AWAKEN_SCROLL_BARS);
                        // if the user waits a while w/o moving before the
                        // up, we don't want to do a fling
                        if (eventTime - mLastTouchTime <= MIN_FLING_TIME) {
                            if (mVelocityTracker == null) {
                                Log.e(LOGTAG, "Got null mVelocityTracker when "
                                        + "mPreventDefault = "
                                        + mPreventDefault
                                        + " mDeferTouchProcess = "
                                        + mDeferTouchProcess);
                            } else {
                                mVelocityTracker.addMovement(ev);
                            }
                            // set to MOTIONLESS_IGNORE so that it won't keep
                            // removing and sending message in
                            // drawCoreAndCursorRing()
                            mHeldMotionless = MOTIONLESS_IGNORE;
                            doFling();
                            break;
                        } else {
                            if (mScroller.springBack(mScrollX, mScrollY, 0,
                                    computeMaxScrollX(), 0,
                                    computeMaxScrollY())) {
                                invalidate();
                            }
                        }
                        // redraw in high-quality, as we're done dragging
                        mHeldMotionless = MOTIONLESS_TRUE;
                        invalidate();
                        // fall through
                    case TOUCH_DRAG_START_MODE:
                        // TOUCH_DRAG_START_MODE should not happen for the real
                        // device as we almost certain will get a MOVE. But this
                        // is possible on emulator.
                        mLastVelocity = 0;
                        WebViewCore.resumePriority();
                        if (!mSelectingText) {
                            WebViewCore.resumeUpdatePicture(mWebViewCore);
                        }
                        break;
                }
                stopTouch();
                break;
            }
            case MotionEvent.ACTION_CANCEL: {
                if (mTouchMode == TOUCH_DRAG_MODE) {
                    mScroller.springBack(mScrollX, mScrollY, 0,
                            computeMaxScrollX(), 0, computeMaxScrollY());
                    invalidate();
                }
                cancelWebCoreTouchEvent(contentX, contentY, false);
                cancelTouch();
                break;
            }
        }
        return true;
    }

    private void passMultiTouchToWebKit(MotionEvent ev, long sequence) {
        TouchEventData ted = new TouchEventData();
        ted.mAction = ev.getActionMasked();
        final int count = ev.getPointerCount();
        ted.mIds = new int[count];
        ted.mPoints = new Point[count];
        ted.mPointsInView = new Point[count];
        for (int c = 0; c < count; c++) {
            ted.mIds[c] = ev.getPointerId(c);
            int x = viewToContentX((int) ev.getX(c) + mScrollX);
            int y = viewToContentY((int) ev.getY(c) + mScrollY);
            ted.mPoints[c] = new Point(x, y);
            ted.mPointsInView[c] = new Point((int) ev.getX(c), (int) ev.getY(c));
        }
        if (ted.mAction == MotionEvent.ACTION_POINTER_DOWN
            || ted.mAction == MotionEvent.ACTION_POINTER_UP) {
            ted.mActionIndex = ev.getActionIndex();
        }
        ted.mMetaState = ev.getMetaState();
        ted.mReprocess = true;
        ted.mMotionEvent = MotionEvent.obtain(ev);
        ted.mSequence = sequence;
        mTouchEventQueue.preQueueTouchEventData(ted);
        mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
        cancelLongPress();
        mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);
    }

    void handleMultiTouchInWebView(MotionEvent ev) {
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "multi-touch: " + ev + " at " + ev.getEventTime()
                + " mTouchMode=" + mTouchMode
                + " numPointers=" + ev.getPointerCount()
                + " scrolloffset=(" + mScrollX + "," + mScrollY + ")");
        }

        final ScaleGestureDetector detector =
            mZoomManager.getMultiTouchGestureDetector();

        // A few apps use WebView but don't instantiate gesture detector.
        // We don't need to support multi touch for them.
        if (detector == null) return;

        float x = ev.getX();
        float y = ev.getY();

        if (mPreventDefault != PREVENT_DEFAULT_YES) {
            detector.onTouchEvent(ev);

            if (detector.isInProgress()) {
                if (DebugFlags.WEB_VIEW) {
                    Log.v(LOGTAG, "detector is in progress");
                }
                mLastTouchTime = ev.getEventTime();
                x = detector.getFocusX();
                y = detector.getFocusY();

                cancelLongPress();
                mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);
                if (!mZoomManager.supportsPanDuringZoom()) {
                    return;
                }
                mTouchMode = TOUCH_DRAG_MODE;
                if (mVelocityTracker == null) {
                    mVelocityTracker = VelocityTracker.obtain();
                }
            }
        }

        int action = ev.getActionMasked();
        if (action == MotionEvent.ACTION_POINTER_DOWN) {
            cancelTouch();
            action = MotionEvent.ACTION_DOWN;
        } else if (action == MotionEvent.ACTION_POINTER_UP && ev.getPointerCount() >= 2) {
            // set mLastTouchX/Y to the remaining points for multi-touch.
            mLastTouchX = Math.round(x);
            mLastTouchY = Math.round(y);
        } else if (action == MotionEvent.ACTION_MOVE) {
            // negative x or y indicate it is on the edge, skip it.
            if (x < 0 || y < 0) {
                return;
            }
        }

        handleTouchEventCommon(ev, action, Math.round(x), Math.round(y));
    }

    private void cancelWebCoreTouchEvent(int x, int y, boolean removeEvents) {
        if (shouldForwardTouchEvent()) {
            if (removeEvents) {
                mWebViewCore.removeMessages(EventHub.TOUCH_EVENT);
            }
            TouchEventData ted = new TouchEventData();
            ted.mIds = new int[1];
            ted.mIds[0] = 0;
            ted.mPoints = new Point[1];
            ted.mPoints[0] = new Point(x, y);
            ted.mPointsInView = new Point[1];
            int viewX = contentToViewX(x) - mScrollX;
            int viewY = contentToViewY(y) - mScrollY;
            ted.mPointsInView[0] = new Point(viewX, viewY);
            ted.mAction = MotionEvent.ACTION_CANCEL;
            ted.mNativeLayer = nativeScrollableLayer(
                    x, y, ted.mNativeLayerRect, null);
            ted.mSequence = mTouchEventQueue.nextTouchSequence();
            mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
            mPreventDefault = PREVENT_DEFAULT_IGNORE;

            if (removeEvents) {
                // Mark this after sending the message above; we should
                // be willing to ignore the cancel event that we just sent.
                mTouchEventQueue.ignoreCurrentlyMissingEvents();
            }
        }
    }

    private void startTouch(float x, float y, long eventTime) {
        // Remember where the motion event started
        mStartTouchX = mLastTouchX = Math.round(x);
        mStartTouchY = mLastTouchY = Math.round(y);
        mLastTouchTime = eventTime;
        mVelocityTracker = VelocityTracker.obtain();
        mSnapScrollMode = SNAP_NONE;
        mPrivateHandler.sendEmptyMessageDelayed(UPDATE_SELECTION,
                ViewConfiguration.getTapTimeout());
    }

    private void startDrag() {
        WebViewCore.reducePriority();
        // to get better performance, pause updating the picture
        WebViewCore.pauseUpdatePicture(mWebViewCore);
        nativeSetIsScrolling(true);

        if (!mDragFromTextInput) {
            nativeHideCursor();
        }

        if (mHorizontalScrollBarMode != SCROLLBAR_ALWAYSOFF
                || mVerticalScrollBarMode != SCROLLBAR_ALWAYSOFF) {
            mZoomManager.invokeZoomPicker();
        }
    }

    private void doDrag(int deltaX, int deltaY) {
        if ((deltaX | deltaY) != 0) {
            int oldX = mScrollX;
            int oldY = mScrollY;
            int rangeX = computeMaxScrollX();
            int rangeY = computeMaxScrollY();
            // Check for the original scrolling layer in case we change
            // directions.  mTouchMode might be TOUCH_DRAG_MODE if we have
            // reached the edge of a layer but mScrollingLayer will be non-zero
            // if we initiated the drag on a layer.
            if (mCurrentScrollingLayerId != 0) {
                final int contentX = viewToContentDimension(deltaX);
                final int contentY = viewToContentDimension(deltaY);

                // Check the scrolling bounds to see if we will actually do any
                // scrolling.  The rectangle is in document coordinates.
                final int maxX = mScrollingLayerRect.right;
                final int maxY = mScrollingLayerRect.bottom;
                final int resultX = Math.max(0,
                        Math.min(mScrollingLayerRect.left + contentX, maxX));
                final int resultY = Math.max(0,
                        Math.min(mScrollingLayerRect.top + contentY, maxY));

                if (resultX != mScrollingLayerRect.left ||
                        resultY != mScrollingLayerRect.top) {
                    // In case we switched to dragging the page.
                    mTouchMode = TOUCH_DRAG_LAYER_MODE;
                    deltaX = contentX;
                    deltaY = contentY;
                    oldX = mScrollingLayerRect.left;
                    oldY = mScrollingLayerRect.top;
                    rangeX = maxX;
                    rangeY = maxY;
                } else {
                    // Scroll the main page if we are not going to scroll the
                    // layer.  This does not reset mScrollingLayer in case the
                    // user changes directions and the layer can scroll the
                    // other way.
                    mTouchMode = TOUCH_DRAG_MODE;
                }
            }

            if (mOverScrollGlow != null) {
                mOverScrollGlow.setOverScrollDeltas(deltaX, deltaY);
            }

            overScrollBy(deltaX, deltaY, oldX, oldY,
                    rangeX, rangeY,
                    mOverscrollDistance, mOverscrollDistance, true);
            if (mOverScrollGlow != null && mOverScrollGlow.isAnimating()) {
                invalidate();
            }
        }
        mZoomManager.keepZoomPickerVisible();
    }

    private void stopTouch() {
        if (mScroller.isFinished() && !mSelectingText
                && (mTouchMode == TOUCH_DRAG_MODE || mTouchMode == TOUCH_DRAG_LAYER_MODE)) {
            WebViewCore.resumePriority();
            WebViewCore.resumeUpdatePicture(mWebViewCore);
            nativeSetIsScrolling(false);
        }

        // we also use mVelocityTracker == null to tell us that we are
        // not "moving around", so we can take the slower/prettier
        // mode in the drawing code
        if (mVelocityTracker != null) {
            mVelocityTracker.recycle();
            mVelocityTracker = null;
        }

        // Release any pulled glows
        if (mOverScrollGlow != null) {
            mOverScrollGlow.releaseAll();
        }

        if (mSelectingText) {
            mSelectionStarted = false;
            syncSelectionCursors();
            invalidate();
        }
    }

    private void cancelTouch() {
        // we also use mVelocityTracker == null to tell us that we are
        // not "moving around", so we can take the slower/prettier
        // mode in the drawing code
        if (mVelocityTracker != null) {
            mVelocityTracker.recycle();
            mVelocityTracker = null;
        }

        if ((mTouchMode == TOUCH_DRAG_MODE
                || mTouchMode == TOUCH_DRAG_LAYER_MODE) && !mSelectingText) {
            WebViewCore.resumePriority();
            WebViewCore.resumeUpdatePicture(mWebViewCore);
            nativeSetIsScrolling(false);
        }
        mPrivateHandler.removeMessages(SWITCH_TO_SHORTPRESS);
        mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);
        mPrivateHandler.removeMessages(DRAG_HELD_MOTIONLESS);
        mPrivateHandler.removeMessages(AWAKEN_SCROLL_BARS);
        if (sDisableNavcache) {
            removeTouchHighlight();
        }
        mHeldMotionless = MOTIONLESS_TRUE;
        mTouchMode = TOUCH_DONE_MODE;
        nativeHideCursor();
    }

    @Override
    public boolean onGenericMotionEvent(MotionEvent event) {
        if ((event.getSource() & InputDevice.SOURCE_CLASS_POINTER) != 0) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_SCROLL: {
                    final float vscroll;
                    final float hscroll;
                    if ((event.getMetaState() & KeyEvent.META_SHIFT_ON) != 0) {
                        vscroll = 0;
                        hscroll = event.getAxisValue(MotionEvent.AXIS_VSCROLL);
                    } else {
                        vscroll = -event.getAxisValue(MotionEvent.AXIS_VSCROLL);
                        hscroll = event.getAxisValue(MotionEvent.AXIS_HSCROLL);
                    }
                    if (hscroll != 0 || vscroll != 0) {
                        final int vdelta = (int) (vscroll * getVerticalScrollFactor());
                        final int hdelta = (int) (hscroll * getHorizontalScrollFactor());
                        if (pinScrollBy(hdelta, vdelta, false, 0)) {
                            return true;
                        }
                    }
                }
            }
        }
        return super.onGenericMotionEvent(event);
    }

    private long mTrackballFirstTime = 0;
    private long mTrackballLastTime = 0;
    private float mTrackballRemainsX = 0.0f;
    private float mTrackballRemainsY = 0.0f;
    private int mTrackballXMove = 0;
    private int mTrackballYMove = 0;
    private boolean mSelectingText = false;
    private boolean mSelectionStarted = false;
    private static final int TRACKBALL_KEY_TIMEOUT = 1000;
    private static final int TRACKBALL_TIMEOUT = 200;
    private static final int TRACKBALL_WAIT = 100;
    private static final int TRACKBALL_SCALE = 400;
    private static final int TRACKBALL_SCROLL_COUNT = 5;
    private static final int TRACKBALL_MOVE_COUNT = 10;
    private static final int TRACKBALL_MULTIPLIER = 3;
    private static final int SELECT_CURSOR_OFFSET = 16;
    private static final int SELECT_SCROLL = 5;
    private int mSelectX = 0;
    private int mSelectY = 0;
    private boolean mFocusSizeChanged = false;
    private boolean mTrackballDown = false;
    private long mTrackballUpTime = 0;
    private long mLastCursorTime = 0;
    private Rect mLastCursorBounds;

    // Set by default; BrowserActivity clears to interpret trackball data
    // directly for movement. Currently, the framework only passes
    // arrow key events, not trackball events, from one child to the next
    private boolean mMapTrackballToArrowKeys = true;

    private DrawData mDelaySetPicture;
    private DrawData mLoadedPicture;

    public void setMapTrackballToArrowKeys(boolean setMap) {
        checkThread();
        mMapTrackballToArrowKeys = setMap;
    }

    void resetTrackballTime() {
        mTrackballLastTime = 0;
    }

    @Override
    public boolean onTrackballEvent(MotionEvent ev) {
        long time = ev.getEventTime();
        if ((ev.getMetaState() & KeyEvent.META_ALT_ON) != 0) {
            if (ev.getY() > 0) pageDown(true);
            if (ev.getY() < 0) pageUp(true);
            return true;
        }
        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
            if (mSelectingText) {
                return true; // discard press if copy in progress
            }
            mTrackballDown = true;
            if (mNativeClass == 0) {
                return false;
            }
            if (time - mLastCursorTime <= TRACKBALL_TIMEOUT
                    && !mLastCursorBounds.equals(nativeGetCursorRingBounds())) {
                nativeSelectBestAt(mLastCursorBounds);
            }
            if (DebugFlags.WEB_VIEW) {
                Log.v(LOGTAG, "onTrackballEvent down ev=" + ev
                        + " time=" + time
                        + " mLastCursorTime=" + mLastCursorTime);
            }
            if (isInTouchMode()) requestFocusFromTouch();
            return false; // let common code in onKeyDown at it
        }
        if (ev.getAction() == MotionEvent.ACTION_UP) {
            // LONG_PRESS_CENTER is set in common onKeyDown
            mPrivateHandler.removeMessages(LONG_PRESS_CENTER);
            mTrackballDown = false;
            mTrackballUpTime = time;
            if (mSelectingText) {
                copySelection();
                selectionDone();
                return true; // discard press if copy in progress
            }
            if (DebugFlags.WEB_VIEW) {
                Log.v(LOGTAG, "onTrackballEvent up ev=" + ev
                        + " time=" + time
                );
            }
            return false; // let common code in onKeyUp at it
        }
        if ((mMapTrackballToArrowKeys && (ev.getMetaState() & KeyEvent.META_SHIFT_ON) == 0) ||
                AccessibilityManager.getInstance(mContext).isEnabled()) {
            if (DebugFlags.WEB_VIEW) Log.v(LOGTAG, "onTrackballEvent gmail quit");
            return false;
        }
        if (mTrackballDown) {
            if (DebugFlags.WEB_VIEW) Log.v(LOGTAG, "onTrackballEvent down quit");
            return true; // discard move if trackball is down
        }
        if (time - mTrackballUpTime < TRACKBALL_TIMEOUT) {
            if (DebugFlags.WEB_VIEW) Log.v(LOGTAG, "onTrackballEvent up timeout quit");
            return true;
        }
        // TODO: alternatively we can do panning as touch does
        switchOutDrawHistory();
        if (time - mTrackballLastTime > TRACKBALL_TIMEOUT) {
            if (DebugFlags.WEB_VIEW) {
                Log.v(LOGTAG, "onTrackballEvent time="
                        + time + " last=" + mTrackballLastTime);
            }
            mTrackballFirstTime = time;
            mTrackballXMove = mTrackballYMove = 0;
        }
        mTrackballLastTime = time;
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "onTrackballEvent ev=" + ev + " time=" + time);
        }
        mTrackballRemainsX += ev.getX();
        mTrackballRemainsY += ev.getY();
        doTrackball(time, ev.getMetaState());
        return true;
    }

    private int scaleTrackballX(float xRate, int width) {
        int xMove = (int) (xRate / TRACKBALL_SCALE * width);
        int nextXMove = xMove;
        if (xMove > 0) {
            if (xMove > mTrackballXMove) {
                xMove -= mTrackballXMove;
            }
        } else if (xMove < mTrackballXMove) {
            xMove -= mTrackballXMove;
        }
        mTrackballXMove = nextXMove;
        return xMove;
    }

    private int scaleTrackballY(float yRate, int height) {
        int yMove = (int) (yRate / TRACKBALL_SCALE * height);
        int nextYMove = yMove;
        if (yMove > 0) {
            if (yMove > mTrackballYMove) {
                yMove -= mTrackballYMove;
            }
        } else if (yMove < mTrackballYMove) {
            yMove -= mTrackballYMove;
        }
        mTrackballYMove = nextYMove;
        return yMove;
    }

    private int keyCodeToSoundsEffect(int keyCode) {
        switch(keyCode) {
            case KeyEvent.KEYCODE_DPAD_UP:
                return SoundEffectConstants.NAVIGATION_UP;
            case KeyEvent.KEYCODE_DPAD_RIGHT:
                return SoundEffectConstants.NAVIGATION_RIGHT;
            case KeyEvent.KEYCODE_DPAD_DOWN:
                return SoundEffectConstants.NAVIGATION_DOWN;
            case KeyEvent.KEYCODE_DPAD_LEFT:
                return SoundEffectConstants.NAVIGATION_LEFT;
        }
        throw new IllegalArgumentException("keyCode must be one of " +
                "{KEYCODE_DPAD_UP, KEYCODE_DPAD_RIGHT, KEYCODE_DPAD_DOWN, " +
                "KEYCODE_DPAD_LEFT}.");
    }

    private void doTrackball(long time, int metaState) {
        int elapsed = (int) (mTrackballLastTime - mTrackballFirstTime);
        if (elapsed == 0) {
            elapsed = TRACKBALL_TIMEOUT;
        }
        float xRate = mTrackballRemainsX * 1000 / elapsed;
        float yRate = mTrackballRemainsY * 1000 / elapsed;
        int viewWidth = getViewWidth();
        int viewHeight = getViewHeight();
        float ax = Math.abs(xRate);
        float ay = Math.abs(yRate);
        float maxA = Math.max(ax, ay);
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "doTrackball elapsed=" + elapsed
                    + " xRate=" + xRate
                    + " yRate=" + yRate
                    + " mTrackballRemainsX=" + mTrackballRemainsX
                    + " mTrackballRemainsY=" + mTrackballRemainsY);
        }
        int width = mContentWidth - viewWidth;
        int height = mContentHeight - viewHeight;
        if (width < 0) width = 0;
        if (height < 0) height = 0;
        ax = Math.abs(mTrackballRemainsX * TRACKBALL_MULTIPLIER);
        ay = Math.abs(mTrackballRemainsY * TRACKBALL_MULTIPLIER);
        maxA = Math.max(ax, ay);
        int count = Math.max(0, (int) maxA);
        int oldScrollX = mScrollX;
        int oldScrollY = mScrollY;
        if (count > 0) {
            int selectKeyCode = ax < ay ? mTrackballRemainsY < 0 ?
                    KeyEvent.KEYCODE_DPAD_UP : KeyEvent.KEYCODE_DPAD_DOWN :
                    mTrackballRemainsX < 0 ? KeyEvent.KEYCODE_DPAD_LEFT :
                    KeyEvent.KEYCODE_DPAD_RIGHT;
            count = Math.min(count, TRACKBALL_MOVE_COUNT);
            if (DebugFlags.WEB_VIEW) {
                Log.v(LOGTAG, "doTrackball keyCode=" + selectKeyCode
                        + " count=" + count
                        + " mTrackballRemainsX=" + mTrackballRemainsX
                        + " mTrackballRemainsY=" + mTrackballRemainsY);
            }
            if (mNativeClass != 0 && nativePageShouldHandleShiftAndArrows()) {
                for (int i = 0; i < count; i++) {
                    letPageHandleNavKey(selectKeyCode, time, true, metaState);
                }
                letPageHandleNavKey(selectKeyCode, time, false, metaState);
            } else if (navHandledKey(selectKeyCode, count, false, time)) {
                playSoundEffect(keyCodeToSoundsEffect(selectKeyCode));
            }
            mTrackballRemainsX = mTrackballRemainsY = 0;
        }
        if (count >= TRACKBALL_SCROLL_COUNT) {
            int xMove = scaleTrackballX(xRate, width);
            int yMove = scaleTrackballY(yRate, height);
            if (DebugFlags.WEB_VIEW) {
                Log.v(LOGTAG, "doTrackball pinScrollBy"
                        + " count=" + count
                        + " xMove=" + xMove + " yMove=" + yMove
                        + " mScrollX-oldScrollX=" + (mScrollX-oldScrollX)
                        + " mScrollY-oldScrollY=" + (mScrollY-oldScrollY)
                        );
            }
            if (Math.abs(mScrollX - oldScrollX) > Math.abs(xMove)) {
                xMove = 0;
            }
            if (Math.abs(mScrollY - oldScrollY) > Math.abs(yMove)) {
                yMove = 0;
            }
            if (xMove != 0 || yMove != 0) {
                pinScrollBy(xMove, yMove, true, 0);
            }
        }
    }

    /**
     * Compute the maximum horizontal scroll position. Used by {@link OverScrollGlow}.
     * @return Maximum horizontal scroll position within real content
     */
    int computeMaxScrollX() {
        return Math.max(computeRealHorizontalScrollRange() - getViewWidth(), 0);
    }

    /**
     * Compute the maximum vertical scroll position. Used by {@link OverScrollGlow}.
     * @return Maximum vertical scroll position within real content
     */
    int computeMaxScrollY() {
        return Math.max(computeRealVerticalScrollRange() + getTitleHeight()
                - getViewHeightWithTitle(), 0);
    }

    boolean updateScrollCoordinates(int x, int y) {
        int oldX = mScrollX;
        int oldY = mScrollY;
        mScrollX = x;
        mScrollY = y;
        if (oldX != mScrollX || oldY != mScrollY) {
            onScrollChanged(mScrollX, mScrollY, oldX, oldY);
            return true;
        } else {
            return false;
        }
    }

    public void flingScroll(int vx, int vy) {
        checkThread();
        mScroller.fling(mScrollX, mScrollY, vx, vy, 0, computeMaxScrollX(), 0,
                computeMaxScrollY(), mOverflingDistance, mOverflingDistance);
        invalidate();
    }

    private void doFling() {
        if (mVelocityTracker == null) {
            return;
        }
        int maxX = computeMaxScrollX();
        int maxY = computeMaxScrollY();

        mVelocityTracker.computeCurrentVelocity(1000, mMaximumFling);
        int vx = (int) mVelocityTracker.getXVelocity();
        int vy = (int) mVelocityTracker.getYVelocity();

        int scrollX = mScrollX;
        int scrollY = mScrollY;
        int overscrollDistance = mOverscrollDistance;
        int overflingDistance = mOverflingDistance;

        // Use the layer's scroll data if applicable.
        if (mTouchMode == TOUCH_DRAG_LAYER_MODE) {
            scrollX = mScrollingLayerRect.left;
            scrollY = mScrollingLayerRect.top;
            maxX = mScrollingLayerRect.right;
            maxY = mScrollingLayerRect.bottom;
            // No overscrolling for layers.
            overscrollDistance = overflingDistance = 0;
        }

        if (mSnapScrollMode != SNAP_NONE) {
            if ((mSnapScrollMode & SNAP_X) == SNAP_X) {
                vy = 0;
            } else {
                vx = 0;
            }
        }
        if ((maxX == 0 && vy == 0) || (maxY == 0 && vx == 0)) {
            WebViewCore.resumePriority();
            if (!mSelectingText) {
                WebViewCore.resumeUpdatePicture(mWebViewCore);
            }
            if (mScroller.springBack(scrollX, scrollY, 0, maxX, 0, maxY)) {
                invalidate();
            }
            return;
        }
        float currentVelocity = mScroller.getCurrVelocity();
        float velocity = (float) Math.hypot(vx, vy);
        if (mLastVelocity > 0 && currentVelocity > 0 && velocity
                > mLastVelocity * MINIMUM_VELOCITY_RATIO_FOR_ACCELERATION) {
            float deltaR = (float) (Math.abs(Math.atan2(mLastVelY, mLastVelX)
                    - Math.atan2(vy, vx)));
            final float circle = (float) (Math.PI) * 2.0f;
            if (deltaR > circle * 0.9f || deltaR < circle * 0.1f) {
                vx += currentVelocity * mLastVelX / mLastVelocity;
                vy += currentVelocity * mLastVelY / mLastVelocity;
                velocity = (float) Math.hypot(vx, vy);
                if (DebugFlags.WEB_VIEW) {
                    Log.v(LOGTAG, "doFling vx= " + vx + " vy=" + vy);
                }
            } else if (DebugFlags.WEB_VIEW) {
                Log.v(LOGTAG, "doFling missed " + deltaR / circle);
            }
        } else if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "doFling start last=" + mLastVelocity
                    + " current=" + currentVelocity
                    + " vx=" + vx + " vy=" + vy
                    + " maxX=" + maxX + " maxY=" + maxY
                    + " scrollX=" + scrollX + " scrollY=" + scrollY
                    + " layer=" + mCurrentScrollingLayerId);
        }

        // Allow sloppy flings without overscrolling at the edges.
        if ((scrollX == 0 || scrollX == maxX) && Math.abs(vx) < Math.abs(vy)) {
            vx = 0;
        }
        if ((scrollY == 0 || scrollY == maxY) && Math.abs(vy) < Math.abs(vx)) {
            vy = 0;
        }

        if (overscrollDistance < overflingDistance) {
            if ((vx > 0 && scrollX == -overscrollDistance) ||
                    (vx < 0 && scrollX == maxX + overscrollDistance)) {
                vx = 0;
            }
            if ((vy > 0 && scrollY == -overscrollDistance) ||
                    (vy < 0 && scrollY == maxY + overscrollDistance)) {
                vy = 0;
            }
        }

        mLastVelX = vx;
        mLastVelY = vy;
        mLastVelocity = velocity;

        // no horizontal overscroll if the content just fits
        mScroller.fling(scrollX, scrollY, -vx, -vy, 0, maxX, 0, maxY,
                maxX == 0 ? 0 : overflingDistance, overflingDistance);
        // Duration is calculated based on velocity. With range boundaries and overscroll
        // we may not know how long the final animation will take. (Hence the deprecation
        // warning on the call below.) It's not a big deal for scroll bars but if webcore
        // resumes during this effect we will take a performance hit. See computeScroll;
        // we resume webcore there when the animation is finished.
        final int time = mScroller.getDuration();

        // Suppress scrollbars for layer scrolling.
        if (mTouchMode != TOUCH_DRAG_LAYER_MODE) {
            awakenScrollBars(time);
        }

        invalidate();
    }

    /**
     * Returns a view containing zoom controls i.e. +/- buttons. The caller is
     * in charge of installing this view to the view hierarchy. This view will
     * become visible when the user starts scrolling via touch and fade away if
     * the user does not interact with it.
     * <p/>
     * API version 3 introduces a built-in zoom mechanism that is shown
     * automatically by the MapView. This is the preferred approach for
     * showing the zoom UI.
     *
     * @deprecated The built-in zoom mechanism is preferred, see
     *             {@link WebSettings#setBuiltInZoomControls(boolean)}.
     */
    @Deprecated
    public View getZoomControls() {
        checkThread();
        if (!getSettings().supportZoom()) {
            Log.w(LOGTAG, "This WebView doesn't support zoom.");
            return null;
        }
        return mZoomManager.getExternalZoomPicker();
    }

    void dismissZoomControl() {
        mZoomManager.dismissZoomPicker();
    }

    float getDefaultZoomScale() {
        return mZoomManager.getDefaultScale();
    }

    /**
     * Return the overview scale of the WebView
     * @return The overview scale.
     */
    float getZoomOverviewScale() {
        return mZoomManager.getZoomOverviewScale();
    }

    /**
     * @return TRUE if the WebView can be zoomed in.
     */
    public boolean canZoomIn() {
        checkThread();
        return mZoomManager.canZoomIn();
    }

    /**
     * @return TRUE if the WebView can be zoomed out.
     */
    public boolean canZoomOut() {
        checkThread();
        return mZoomManager.canZoomOut();
    }

    /**
     * Perform zoom in in the webview
     * @return TRUE if zoom in succeeds. FALSE if no zoom changes.
     */
    public boolean zoomIn() {
        checkThread();
        return mZoomManager.zoomIn();
    }

    /**
     * Perform zoom out in the webview
     * @return TRUE if zoom out succeeds. FALSE if no zoom changes.
     */
    public boolean zoomOut() {
        checkThread();
        return mZoomManager.zoomOut();
    }

    /**
     * This selects the best clickable target at mLastTouchX and mLastTouchY
     * and calls showCursorTimed on the native side
     */
    private void updateSelection() {
        if (mNativeClass == 0 || sDisableNavcache) {
            return;
        }
        mPrivateHandler.removeMessages(UPDATE_SELECTION);
        // mLastTouchX and mLastTouchY are the point in the current viewport
        int contentX = viewToContentX(mLastTouchX + mScrollX);
        int contentY = viewToContentY(mLastTouchY + mScrollY);
        int slop = viewToContentDimension(mNavSlop);
        Rect rect = new Rect(contentX - slop, contentY - slop,
                contentX + slop, contentY + slop);
        nativeSelectBestAt(rect);
        mInitialHitTestResult = hitTestResult(null);
    }

    /**
     * Scroll the focused text field to match the WebTextView
     * @param xPercent New x position of the WebTextView from 0 to 1.
     */
    /*package*/ void scrollFocusedTextInputX(float xPercent) {
        if (!inEditingMode() || mWebViewCore == null) {
            return;
        }
        mWebViewCore.sendMessage(EventHub.SCROLL_TEXT_INPUT, 0,
                new Float(xPercent));
    }

    /**
     * Scroll the focused textarea vertically to match the WebTextView
     * @param y New y position of the WebTextView in view coordinates
     */
    /* package */ void scrollFocusedTextInputY(int y) {
        if (!inEditingMode() || mWebViewCore == null) {
            return;
        }
        mWebViewCore.sendMessage(EventHub.SCROLL_TEXT_INPUT, 0, viewToContentDimension(y));
    }

    /**
     * Set our starting point and time for a drag from the WebTextView.
     */
    /*package*/ void initiateTextFieldDrag(float x, float y, long eventTime) {
        if (!inEditingMode()) {
            return;
        }
        mLastTouchX = Math.round(x + mWebTextView.getLeft() - mScrollX);
        mLastTouchY = Math.round(y + mWebTextView.getTop() - mScrollY);
        mLastTouchTime = eventTime;
        if (!mScroller.isFinished()) {
            abortAnimation();
        }
        mSnapScrollMode = SNAP_NONE;
        mVelocityTracker = VelocityTracker.obtain();
        mTouchMode = TOUCH_DRAG_START_MODE;
    }

    /**
     * Given a motion event from the WebTextView, set its location to our
     * coordinates, and handle the event.
     */
    /*package*/ boolean textFieldDrag(MotionEvent event) {
        if (!inEditingMode()) {
            return false;
        }
        mDragFromTextInput = true;
        event.offsetLocation((mWebTextView.getLeft() - mScrollX),
                (mWebTextView.getTop() - mScrollY));
        boolean result = onTouchEvent(event);
        mDragFromTextInput = false;
        return result;
    }

    /**
     * Due a touch up from a WebTextView.  This will be handled by webkit to
     * change the selection.
     * @param event MotionEvent in the WebTextView's coordinates.
     */
    /*package*/ void touchUpOnTextField(MotionEvent event) {
        if (!inEditingMode()) {
            return;
        }
        int x = viewToContentX((int) event.getX() + mWebTextView.getLeft());
        int y = viewToContentY((int) event.getY() + mWebTextView.getTop());
        int slop = viewToContentDimension(mNavSlop);
        nativeMotionUp(x, y, slop);
    }

    /**
     * Called when pressing the center key or trackball on a textfield.
     */
    /*package*/ void centerKeyPressOnTextField() {
        mWebViewCore.sendMessage(EventHub.CLICK, nativeCursorFramePointer(),
                    nativeCursorNodePointer());
    }

    private void doShortPress() {
        if (mNativeClass == 0) {
            return;
        }
        if (mPreventDefault == PREVENT_DEFAULT_YES) {
            return;
        }
        mTouchMode = TOUCH_DONE_MODE;
        updateSelection();
        switchOutDrawHistory();
        // mLastTouchX and mLastTouchY are the point in the current viewport
        int contentX = viewToContentX(mLastTouchX + mScrollX);
        int contentY = viewToContentY(mLastTouchY + mScrollY);
        int slop = viewToContentDimension(mNavSlop);
        if (sDisableNavcache && !mTouchHighlightRegion.isEmpty()) {
            // set mTouchHighlightRequested to 0 to cause an immediate
            // drawing of the touch rings
            mTouchHighlightRequested = 0;
            invalidate(mTouchHighlightRegion.getBounds());
            mPrivateHandler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    removeTouchHighlight();
                }
            }, ViewConfiguration.getPressedStateDuration());
        }
        if (sDisableNavcache) {
            WebViewCore.TouchUpData touchUpData = new WebViewCore.TouchUpData();
            // use "0" as generation id to inform WebKit to use the same x/y as
            // it used when processing GET_TOUCH_HIGHLIGHT_RECTS
            touchUpData.mMoveGeneration = 0;
            mWebViewCore.sendMessage(EventHub.TOUCH_UP, touchUpData);
        } else if (nativePointInNavCache(contentX, contentY, slop)) {
            WebViewCore.MotionUpData motionUpData = new WebViewCore
                    .MotionUpData();
            motionUpData.mFrame = nativeCacheHitFramePointer();
            motionUpData.mNode = nativeCacheHitNodePointer();
            motionUpData.mBounds = nativeCacheHitNodeBounds();
            motionUpData.mX = contentX;
            motionUpData.mY = contentY;
            mWebViewCore.sendMessageAtFrontOfQueue(EventHub.VALID_NODE_BOUNDS,
                    motionUpData);
        } else {
            doMotionUp(contentX, contentY);
        }
    }

    private void doMotionUp(int contentX, int contentY) {
        int slop = viewToContentDimension(mNavSlop);
        if (nativeMotionUp(contentX, contentY, slop) && mLogEvent) {
            EventLog.writeEvent(EventLogTags.BROWSER_SNAP_CENTER);
        }
        if (nativeHasCursorNode() && !nativeCursorIsTextInput()) {
            playSoundEffect(SoundEffectConstants.CLICK);
        }
    }

    void sendPluginDrawMsg() {
        mWebViewCore.sendMessage(EventHub.PLUGIN_SURFACE_READY);
    }

    /**
     * Returns plugin bounds if x/y in content coordinates corresponds to a
     * plugin. Otherwise a NULL rectangle is returned.
     */
    Rect getPluginBounds(int x, int y) {
        int slop = viewToContentDimension(mNavSlop);
        if (nativePointInNavCache(x, y, slop) && nativeCacheHitIsPlugin()) {
            return nativeCacheHitNodeBounds();
        } else {
            return null;
        }
    }

    /*
     * Return true if the rect (e.g. plugin) is fully visible and maximized
     * inside the WebView.
     */
    boolean isRectFitOnScreen(Rect rect) {
        final int rectWidth = rect.width();
        final int rectHeight = rect.height();
        final int viewWidth = getViewWidth();
        final int viewHeight = getViewHeightWithTitle();
        float scale = Math.min((float) viewWidth / rectWidth, (float) viewHeight / rectHeight);
        scale = mZoomManager.computeScaleWithLimits(scale);
        return !mZoomManager.willScaleTriggerZoom(scale)
                && contentToViewX(rect.left) >= mScrollX
                && contentToViewX(rect.right) <= mScrollX + viewWidth
                && contentToViewY(rect.top) >= mScrollY
                && contentToViewY(rect.bottom) <= mScrollY + viewHeight;
    }

    /*
     * Maximize and center the rectangle, specified in the document coordinate
     * space, inside the WebView. If the zoom doesn't need to be changed, do an
     * animated scroll to center it. If the zoom needs to be changed, find the
     * zoom center and do a smooth zoom transition. The rect is in document
     * coordinates
     */
    void centerFitRect(Rect rect) {
        final int rectWidth = rect.width();
        final int rectHeight = rect.height();
        final int viewWidth = getViewWidth();
        final int viewHeight = getViewHeightWithTitle();
        float scale = Math.min((float) viewWidth / rectWidth, (float) viewHeight
                / rectHeight);
        scale = mZoomManager.computeScaleWithLimits(scale);
        if (!mZoomManager.willScaleTriggerZoom(scale)) {
            pinScrollTo(contentToViewX(rect.left + rectWidth / 2) - viewWidth / 2,
                    contentToViewY(rect.top + rectHeight / 2) - viewHeight / 2,
                    true, 0);
        } else {
            float actualScale = mZoomManager.getScale();
            float oldScreenX = rect.left * actualScale - mScrollX;
            float rectViewX = rect.left * scale;
            float rectViewWidth = rectWidth * scale;
            float newMaxWidth = mContentWidth * scale;
            float newScreenX = (viewWidth - rectViewWidth) / 2;
            // pin the newX to the WebView
            if (newScreenX > rectViewX) {
                newScreenX = rectViewX;
            } else if (newScreenX > (newMaxWidth - rectViewX - rectViewWidth)) {
                newScreenX = viewWidth - (newMaxWidth - rectViewX);
            }
            float zoomCenterX = (oldScreenX * scale - newScreenX * actualScale)
                    / (scale - actualScale);
            float oldScreenY = rect.top * actualScale + getTitleHeight()
                    - mScrollY;
            float rectViewY = rect.top * scale + getTitleHeight();
            float rectViewHeight = rectHeight * scale;
            float newMaxHeight = mContentHeight * scale + getTitleHeight();
            float newScreenY = (viewHeight - rectViewHeight) / 2;
            // pin the newY to the WebView
            if (newScreenY > rectViewY) {
                newScreenY = rectViewY;
            } else if (newScreenY > (newMaxHeight - rectViewY - rectViewHeight)) {
                newScreenY = viewHeight - (newMaxHeight - rectViewY);
            }
            float zoomCenterY = (oldScreenY * scale - newScreenY * actualScale)
                    / (scale - actualScale);
            mZoomManager.setZoomCenter(zoomCenterX, zoomCenterY);
            mZoomManager.startZoomAnimation(scale, false);
        }
    }

    // Called by JNI to handle a touch on a node representing an email address,
    // address, or phone number
    private void overrideLoading(String url) {
        mCallbackProxy.uiOverrideUrlLoading(url);
    }

    @Override
    public boolean requestFocus(int direction, Rect previouslyFocusedRect) {
        // FIXME: If a subwindow is showing find, and the user touches the
        // background window, it can steal focus.
        if (mFindIsUp) return false;
        boolean result = false;
        if (inEditingMode()) {
            result = mWebTextView.requestFocus(direction,
                    previouslyFocusedRect);
        } else {
            result = super.requestFocus(direction, previouslyFocusedRect);
            if (mWebViewCore.getSettings().getNeedInitialFocus() && !isInTouchMode()) {
                // For cases such as GMail, where we gain focus from a direction,
                // we want to move to the first available link.
                // FIXME: If there are no visible links, we may not want to
                int fakeKeyDirection = 0;
                switch(direction) {
                    case View.FOCUS_UP:
                        fakeKeyDirection = KeyEvent.KEYCODE_DPAD_UP;
                        break;
                    case View.FOCUS_DOWN:
                        fakeKeyDirection = KeyEvent.KEYCODE_DPAD_DOWN;
                        break;
                    case View.FOCUS_LEFT:
                        fakeKeyDirection = KeyEvent.KEYCODE_DPAD_LEFT;
                        break;
                    case View.FOCUS_RIGHT:
                        fakeKeyDirection = KeyEvent.KEYCODE_DPAD_RIGHT;
                        break;
                    default:
                        return result;
                }
                if (mNativeClass != 0 && !nativeHasCursorNode()) {
                    navHandledKey(fakeKeyDirection, 1, true, 0);
                }
            }
        }
        return result;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);

        int measuredHeight = heightSize;
        int measuredWidth = widthSize;

        // Grab the content size from WebViewCore.
        int contentHeight = contentToViewDimension(mContentHeight);
        int contentWidth = contentToViewDimension(mContentWidth);

//        Log.d(LOGTAG, "------- measure " + heightMode);

        if (heightMode != MeasureSpec.EXACTLY) {
            mHeightCanMeasure = true;
            measuredHeight = contentHeight;
            if (heightMode == MeasureSpec.AT_MOST) {
                // If we are larger than the AT_MOST height, then our height can
                // no longer be measured and we should scroll internally.
                if (measuredHeight > heightSize) {
                    measuredHeight = heightSize;
                    mHeightCanMeasure = false;
                    measuredHeight |= MEASURED_STATE_TOO_SMALL;
                }
            }
        } else {
            mHeightCanMeasure = false;
        }
        if (mNativeClass != 0) {
            nativeSetHeightCanMeasure(mHeightCanMeasure);
        }
        // For the width, always use the given size unless unspecified.
        if (widthMode == MeasureSpec.UNSPECIFIED) {
            mWidthCanMeasure = true;
            measuredWidth = contentWidth;
        } else {
            if (measuredWidth < contentWidth) {
                measuredWidth |= MEASURED_STATE_TOO_SMALL;
            }
            mWidthCanMeasure = false;
        }

        synchronized (this) {
            setMeasuredDimension(measuredWidth, measuredHeight);
        }
    }

    @Override
    public boolean requestChildRectangleOnScreen(View child,
                                                 Rect rect,
                                                 boolean immediate) {
        if (mNativeClass == 0) {
            return false;
        }
        // don't scroll while in zoom animation. When it is done, we will adjust
        // the necessary components (e.g., WebTextView if it is in editing mode)
        if (mZoomManager.isFixedLengthAnimationInProgress()) {
            return false;
        }

        rect.offset(child.getLeft() - child.getScrollX(),
                child.getTop() - child.getScrollY());

        Rect content = new Rect(viewToContentX(mScrollX),
                viewToContentY(mScrollY),
                viewToContentX(mScrollX + getWidth()
                - getVerticalScrollbarWidth()),
                viewToContentY(mScrollY + getViewHeightWithTitle()));
        content = nativeSubtractLayers(content);
        int screenTop = contentToViewY(content.top);
        int screenBottom = contentToViewY(content.bottom);
        int height = screenBottom - screenTop;
        int scrollYDelta = 0;

        if (rect.bottom > screenBottom) {
            int oneThirdOfScreenHeight = height / 3;
            if (rect.height() > 2 * oneThirdOfScreenHeight) {
                // If the rectangle is too tall to fit in the bottom two thirds
                // of the screen, place it at the top.
                scrollYDelta = rect.top - screenTop;
            } else {
                // If the rectangle will still fit on screen, we want its
                // top to be in the top third of the screen.
                scrollYDelta = rect.top - (screenTop + oneThirdOfScreenHeight);
            }
        } else if (rect.top < screenTop) {
            scrollYDelta = rect.top - screenTop;
        }

        int screenLeft = contentToViewX(content.left);
        int screenRight = contentToViewX(content.right);
        int width = screenRight - screenLeft;
        int scrollXDelta = 0;

        if (rect.right > screenRight && rect.left > screenLeft) {
            if (rect.width() > width) {
                scrollXDelta += (rect.left - screenLeft);
            } else {
                scrollXDelta += (rect.right - screenRight);
            }
        } else if (rect.left < screenLeft) {
            scrollXDelta -= (screenLeft - rect.left);
        }

        if ((scrollYDelta | scrollXDelta) != 0) {
            return pinScrollBy(scrollXDelta, scrollYDelta, !immediate, 0);
        }

        return false;
    }

    /* package */ void replaceTextfieldText(int oldStart, int oldEnd,
            String replace, int newStart, int newEnd) {
        WebViewCore.ReplaceTextData arg = new WebViewCore.ReplaceTextData();
        arg.mReplace = replace;
        arg.mNewStart = newStart;
        arg.mNewEnd = newEnd;
        mTextGeneration++;
        arg.mTextGeneration = mTextGeneration;
        mWebViewCore.sendMessage(EventHub.REPLACE_TEXT, oldStart, oldEnd, arg);
    }

    /* package */ void passToJavaScript(String currentText, KeyEvent event) {
        // check if mWebViewCore has been destroyed
        if (mWebViewCore == null) {
            return;
        }
        WebViewCore.JSKeyData arg = new WebViewCore.JSKeyData();
        arg.mEvent = event;
        arg.mCurrentText = currentText;
        // Increase our text generation number, and pass it to webcore thread
        mTextGeneration++;
        mWebViewCore.sendMessage(EventHub.PASS_TO_JS, mTextGeneration, 0, arg);
        // WebKit's document state is not saved until about to leave the page.
        // To make sure the host application, like Browser, has the up to date
        // document state when it goes to background, we force to save the
        // document state.
        mWebViewCore.removeMessages(EventHub.SAVE_DOCUMENT_STATE);
        mWebViewCore.sendMessageDelayed(EventHub.SAVE_DOCUMENT_STATE,
                cursorData(), 1000);
    }

    /**
     * @hide
     */
    public synchronized WebViewCore getWebViewCore() {
        return mWebViewCore;
    }

    /**
     * Used only by TouchEventQueue to store pending touch events.
     */
    private static class QueuedTouch {
        long mSequence;
        MotionEvent mEvent; // Optional
        TouchEventData mTed; // Optional

        QueuedTouch mNext;

        public QueuedTouch set(TouchEventData ted) {
            mSequence = ted.mSequence;
            mTed = ted;
            mEvent = null;
            mNext = null;
            return this;
        }

        public QueuedTouch set(MotionEvent ev, long sequence) {
            mEvent = MotionEvent.obtain(ev);
            mSequence = sequence;
            mTed = null;
            mNext = null;
            return this;
        }

        public QueuedTouch add(QueuedTouch other) {
            if (other.mSequence < mSequence) {
                other.mNext = this;
                return other;
            }

            QueuedTouch insertAt = this;
            while (insertAt.mNext != null && insertAt.mNext.mSequence < other.mSequence) {
                insertAt = insertAt.mNext;
            }
            other.mNext = insertAt.mNext;
            insertAt.mNext = other;
            return this;
        }
    }

    /**
     * WebView handles touch events asynchronously since some events must be passed to WebKit
     * for potentially slower processing. TouchEventQueue serializes touch events regardless
     * of which path they take to ensure that no events are ever processed out of order
     * by WebView.
     */
    private class TouchEventQueue {
        private long mNextTouchSequence = Long.MIN_VALUE + 1;
        private long mLastHandledTouchSequence = Long.MIN_VALUE;
        private long mIgnoreUntilSequence = Long.MIN_VALUE + 1;

        // Events waiting to be processed.
        private QueuedTouch mTouchEventQueue;

        // Known events that are waiting on a response before being enqueued.
        private QueuedTouch mPreQueue;

        // Pool of QueuedTouch objects saved for later use.
        private QueuedTouch mQueuedTouchRecycleBin;
        private int mQueuedTouchRecycleCount;

        private long mLastEventTime = Long.MAX_VALUE;
        private static final int MAX_RECYCLED_QUEUED_TOUCH = 15;

        // milliseconds until we abandon hope of getting all of a previous gesture
        private static final int QUEUED_GESTURE_TIMEOUT = 1000;

        private QueuedTouch obtainQueuedTouch() {
            if (mQueuedTouchRecycleBin != null) {
                QueuedTouch result = mQueuedTouchRecycleBin;
                mQueuedTouchRecycleBin = result.mNext;
                mQueuedTouchRecycleCount--;
                return result;
            }
            return new QueuedTouch();
        }

        /**
         * Allow events with any currently missing sequence numbers to be skipped in processing.
         */
        public void ignoreCurrentlyMissingEvents() {
            mIgnoreUntilSequence = mNextTouchSequence;

            // Run any events we have available and complete, pre-queued or otherwise.
            runQueuedAndPreQueuedEvents();
        }

        private void runQueuedAndPreQueuedEvents() {
            QueuedTouch qd = mPreQueue;
            boolean fromPreQueue = true;
            while (qd != null && qd.mSequence == mLastHandledTouchSequence + 1) {
                handleQueuedTouch(qd);
                QueuedTouch recycleMe = qd;
                if (fromPreQueue) {
                    mPreQueue = qd.mNext;
                } else {
                    mTouchEventQueue = qd.mNext;
                }
                recycleQueuedTouch(recycleMe);
                mLastHandledTouchSequence++;

                long nextPre = mPreQueue != null ? mPreQueue.mSequence : Long.MAX_VALUE;
                long nextQueued = mTouchEventQueue != null ?
                        mTouchEventQueue.mSequence : Long.MAX_VALUE;
                fromPreQueue = nextPre < nextQueued;
                qd = fromPreQueue ? mPreQueue : mTouchEventQueue;
            }
        }

        /**
         * Add a TouchEventData to the pre-queue.
         *
         * An event in the pre-queue is an event that we know about that
         * has been sent to webkit, but that we haven't received back and
         * enqueued into the normal touch queue yet. If webkit ever times
         * out and we need to ignore currently missing events, we'll run
         * events from the pre-queue to patch the holes.
         *
         * @param ted TouchEventData to pre-queue
         */
        public void preQueueTouchEventData(TouchEventData ted) {
            QueuedTouch newTouch = obtainQueuedTouch().set(ted);
            if (mPreQueue == null) {
                mPreQueue = newTouch;
            } else {
                QueuedTouch insertionPoint = mPreQueue;
                while (insertionPoint.mNext != null &&
                        insertionPoint.mNext.mSequence < newTouch.mSequence) {
                    insertionPoint = insertionPoint.mNext;
                }
                newTouch.mNext = insertionPoint.mNext;
                insertionPoint.mNext = newTouch;
            }
        }

        private void recycleQueuedTouch(QueuedTouch qd) {
            if (mQueuedTouchRecycleCount < MAX_RECYCLED_QUEUED_TOUCH) {
                qd.mNext = mQueuedTouchRecycleBin;
                mQueuedTouchRecycleBin = qd;
                mQueuedTouchRecycleCount++;
            }
        }

        /**
         * Reset the touch event queue. This will dump any pending events
         * and reset the sequence numbering.
         */
        public void reset() {
            mNextTouchSequence = Long.MIN_VALUE + 1;
            mLastHandledTouchSequence = Long.MIN_VALUE;
            mIgnoreUntilSequence = Long.MIN_VALUE + 1;
            while (mTouchEventQueue != null) {
                QueuedTouch recycleMe = mTouchEventQueue;
                mTouchEventQueue = mTouchEventQueue.mNext;
                recycleQueuedTouch(recycleMe);
            }
            while (mPreQueue != null) {
                QueuedTouch recycleMe = mPreQueue;
                mPreQueue = mPreQueue.mNext;
                recycleQueuedTouch(recycleMe);
            }
        }

        /**
         * Return the next valid sequence number for tagging incoming touch events.
         * @return The next touch event sequence number
         */
        public long nextTouchSequence() {
            return mNextTouchSequence++;
        }

        /**
         * Enqueue a touch event in the form of TouchEventData.
         * The sequence number will be read from the mSequence field of the argument.
         *
         * If the touch event's sequence number is the next in line to be processed, it will
         * be handled before this method returns. Any subsequent events that have already
         * been queued will also be processed in their proper order.
         *
         * @param ted Touch data to be processed in order.
         * @return true if the event was processed before returning, false if it was just enqueued.
         */
        public boolean enqueueTouchEvent(TouchEventData ted) {
            // Remove from the pre-queue if present
            QueuedTouch preQueue = mPreQueue;
            if (preQueue != null) {
                // On exiting this block, preQueue is set to the pre-queued QueuedTouch object
                // if it was present in the pre-queue, and removed from the pre-queue itself.
                if (preQueue.mSequence == ted.mSequence) {
                    mPreQueue = preQueue.mNext;
                } else {
                    QueuedTouch prev = preQueue;
                    preQueue = null;
                    while (prev.mNext != null) {
                        if (prev.mNext.mSequence == ted.mSequence) {
                            preQueue = prev.mNext;
                            prev.mNext = preQueue.mNext;
                            break;
                        } else {
                            prev = prev.mNext;
                        }
                    }
                }
            }

            if (ted.mSequence < mLastHandledTouchSequence) {
                // Stale event and we already moved on; drop it. (Should not be common.)
                Log.w(LOGTAG, "Stale touch event " + MotionEvent.actionToString(ted.mAction) +
                        " received from webcore; ignoring");
                return false;
            }

            if (dropStaleGestures(ted.mMotionEvent, ted.mSequence)) {
                return false;
            }

            // dropStaleGestures above might have fast-forwarded us to
            // an event we have already.
            runNextQueuedEvents();

            if (mLastHandledTouchSequence + 1 == ted.mSequence) {
                if (preQueue != null) {
                    recycleQueuedTouch(preQueue);
                    preQueue = null;
                }
                handleQueuedTouchEventData(ted);

                mLastHandledTouchSequence++;

                // Do we have any more? Run them if so.
                runNextQueuedEvents();
            } else {
                // Reuse the pre-queued object if we had it.
                QueuedTouch qd = preQueue != null ? preQueue : obtainQueuedTouch().set(ted);
                mTouchEventQueue = mTouchEventQueue == null ? qd : mTouchEventQueue.add(qd);
            }
            return true;
        }

        /**
         * Enqueue a touch event in the form of a MotionEvent from the framework.
         *
         * If the touch event's sequence number is the next in line to be processed, it will
         * be handled before this method returns. Any subsequent events that have already
         * been queued will also be processed in their proper order.
         *
         * @param ev MotionEvent to be processed in order
         */
        public void enqueueTouchEvent(MotionEvent ev) {
            final long sequence = nextTouchSequence();

            if (dropStaleGestures(ev, sequence)) {
                return;
            }

            // dropStaleGestures above might have fast-forwarded us to
            // an event we have already.
            runNextQueuedEvents();

            if (mLastHandledTouchSequence + 1 == sequence) {
                handleQueuedMotionEvent(ev);

                mLastHandledTouchSequence++;

                // Do we have any more? Run them if so.
                runNextQueuedEvents();
            } else {
                QueuedTouch qd = obtainQueuedTouch().set(ev, sequence);
                mTouchEventQueue = mTouchEventQueue == null ? qd : mTouchEventQueue.add(qd);
            }
        }

        private void runNextQueuedEvents() {
            QueuedTouch qd = mTouchEventQueue;
            while (qd != null && qd.mSequence == mLastHandledTouchSequence + 1) {
                handleQueuedTouch(qd);
                QueuedTouch recycleMe = qd;
                qd = qd.mNext;
                recycleQueuedTouch(recycleMe);
                mLastHandledTouchSequence++;
            }
            mTouchEventQueue = qd;
        }

        private boolean dropStaleGestures(MotionEvent ev, long sequence) {
            if (ev != null && ev.getAction() == MotionEvent.ACTION_MOVE && !mConfirmMove) {
                // This is to make sure that we don't attempt to process a tap
                // or long press when webkit takes too long to get back to us.
                // The movement will be properly confirmed when we process the
                // enqueued event later.
                final int dx = Math.round(ev.getX()) - mLastTouchX;
                final int dy = Math.round(ev.getY()) - mLastTouchY;
                if (dx * dx + dy * dy > mTouchSlopSquare) {
                    mPrivateHandler.removeMessages(SWITCH_TO_SHORTPRESS);
                    mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);
                }
            }

            if (mTouchEventQueue == null) {
                return sequence <= mLastHandledTouchSequence;
            }

            // If we have a new down event and it's been a while since the last event
            // we saw, catch up as best we can and keep going.
            if (ev != null && ev.getAction() == MotionEvent.ACTION_DOWN) {
                long eventTime = ev.getEventTime();
                long lastHandledEventTime = mLastEventTime;
                if (eventTime > lastHandledEventTime + QUEUED_GESTURE_TIMEOUT) {
                    Log.w(LOGTAG, "Got ACTION_DOWN but still waiting on stale event. " +
                            "Catching up.");
                    runQueuedAndPreQueuedEvents();

                    // Drop leftovers that we truly don't have.
                    QueuedTouch qd = mTouchEventQueue;
                    while (qd != null && qd.mSequence < sequence) {
                        QueuedTouch recycleMe = qd;
                        qd = qd.mNext;
                        recycleQueuedTouch(recycleMe);
                    }
                    mTouchEventQueue = qd;
                    mLastHandledTouchSequence = sequence - 1;
                }
            }

            if (mIgnoreUntilSequence - 1 > mLastHandledTouchSequence) {
                QueuedTouch qd = mTouchEventQueue;
                while (qd != null && qd.mSequence < mIgnoreUntilSequence) {
                    QueuedTouch recycleMe = qd;
                    qd = qd.mNext;
                    recycleQueuedTouch(recycleMe);
                }
                mTouchEventQueue = qd;
                mLastHandledTouchSequence = mIgnoreUntilSequence - 1;
            }

            if (mPreQueue != null) {
                // Drop stale prequeued events
                QueuedTouch qd = mPreQueue;
                while (qd != null && qd.mSequence < mIgnoreUntilSequence) {
                    QueuedTouch recycleMe = qd;
                    qd = qd.mNext;
                    recycleQueuedTouch(recycleMe);
                }
                mPreQueue = qd;
            }

            return sequence <= mLastHandledTouchSequence;
        }

        private void handleQueuedTouch(QueuedTouch qt) {
            if (qt.mTed != null) {
                handleQueuedTouchEventData(qt.mTed);
            } else {
                handleQueuedMotionEvent(qt.mEvent);
                qt.mEvent.recycle();
            }
        }

        private void handleQueuedMotionEvent(MotionEvent ev) {
            mLastEventTime = ev.getEventTime();
            int action = ev.getActionMasked();
            if (ev.getPointerCount() > 1) {  // Multi-touch
                handleMultiTouchInWebView(ev);
            } else {
                final ScaleGestureDetector detector = mZoomManager.getMultiTouchGestureDetector();
                if (detector != null && mPreventDefault != PREVENT_DEFAULT_YES) {
                    // ScaleGestureDetector needs a consistent event stream to operate properly.
                    // It won't take any action with fewer than two pointers, but it needs to
                    // update internal bookkeeping state.
                    detector.onTouchEvent(ev);
                }

                handleTouchEventCommon(ev, action, Math.round(ev.getX()), Math.round(ev.getY()));
            }
        }

        private void handleQueuedTouchEventData(TouchEventData ted) {
            if (ted.mMotionEvent != null) {
                mLastEventTime = ted.mMotionEvent.getEventTime();
            }
            if (!ted.mReprocess) {
                if (ted.mAction == MotionEvent.ACTION_DOWN
                        && mPreventDefault == PREVENT_DEFAULT_MAYBE_YES) {
                    // if prevent default is called from WebCore, UI
                    // will not handle the rest of the touch events any
                    // more.
                    mPreventDefault = ted.mNativeResult ? PREVENT_DEFAULT_YES
                            : PREVENT_DEFAULT_NO_FROM_TOUCH_DOWN;
                } else if (ted.mAction == MotionEvent.ACTION_MOVE
                        && mPreventDefault == PREVENT_DEFAULT_NO_FROM_TOUCH_DOWN) {
                    // the return for the first ACTION_MOVE will decide
                    // whether UI will handle touch or not. Currently no
                    // support for alternating prevent default
                    mPreventDefault = ted.mNativeResult ? PREVENT_DEFAULT_YES
                            : PREVENT_DEFAULT_NO;
                }
                if (mPreventDefault == PREVENT_DEFAULT_YES) {
                    mTouchHighlightRegion.setEmpty();
                }
            } else {
                if (ted.mPoints.length > 1) {  // multi-touch
                    if (!ted.mNativeResult && mPreventDefault != PREVENT_DEFAULT_YES) {
                        mPreventDefault = PREVENT_DEFAULT_NO;
                        handleMultiTouchInWebView(ted.mMotionEvent);
                    } else {
                        mPreventDefault = PREVENT_DEFAULT_YES;
                    }
                    return;
                }

                // prevent default is not called in WebCore, so the
                // message needs to be reprocessed in UI
                if (!ted.mNativeResult) {
                    // Following is for single touch.
                    switch (ted.mAction) {
                        case MotionEvent.ACTION_DOWN:
                            mLastDeferTouchX = ted.mPointsInView[0].x;
                            mLastDeferTouchY = ted.mPointsInView[0].y;
                            mDeferTouchMode = TOUCH_INIT_MODE;
                            break;
                        case MotionEvent.ACTION_MOVE: {
                            // no snapping in defer process
                            int x = ted.mPointsInView[0].x;
                            int y = ted.mPointsInView[0].y;

                            if (mDeferTouchMode != TOUCH_DRAG_MODE) {
                                mDeferTouchMode = TOUCH_DRAG_MODE;
                                mLastDeferTouchX = x;
                                mLastDeferTouchY = y;
                                startScrollingLayer(x, y);
                                startDrag();
                            }
                            int deltaX = pinLocX((int) (mScrollX
                                    + mLastDeferTouchX - x))
                                    - mScrollX;
                            int deltaY = pinLocY((int) (mScrollY
                                    + mLastDeferTouchY - y))
                                    - mScrollY;
                            doDrag(deltaX, deltaY);
                            if (deltaX != 0) mLastDeferTouchX = x;
                            if (deltaY != 0) mLastDeferTouchY = y;
                            break;
                        }
                        case MotionEvent.ACTION_UP:
                        case MotionEvent.ACTION_CANCEL:
                            if (mDeferTouchMode == TOUCH_DRAG_MODE) {
                                // no fling in defer process
                                mScroller.springBack(mScrollX, mScrollY, 0,
                                        computeMaxScrollX(), 0,
                                        computeMaxScrollY());
                                invalidate();
                                WebViewCore.resumePriority();
                                WebViewCore.resumeUpdatePicture(mWebViewCore);
                            }
                            mDeferTouchMode = TOUCH_DONE_MODE;
                            break;
                        case WebViewCore.ACTION_DOUBLETAP:
                            // doDoubleTap() needs mLastTouchX/Y as anchor
                            mLastDeferTouchX = ted.mPointsInView[0].x;
                            mLastDeferTouchY = ted.mPointsInView[0].y;
                            mZoomManager.handleDoubleTap(mLastTouchX, mLastTouchY);
                            mDeferTouchMode = TOUCH_DONE_MODE;
                            break;
                        case WebViewCore.ACTION_LONGPRESS:
                            HitTestResult hitTest = getHitTestResult();
                            if (hitTest != null && hitTest.mType
                                    != HitTestResult.UNKNOWN_TYPE) {
                                performLongClick();
                            }
                            mDeferTouchMode = TOUCH_DONE_MODE;
                            break;
                    }
                }
            }
        }
    }

    //-------------------------------------------------------------------------
    // Methods can be called from a separate thread, like WebViewCore
    // If it needs to call the View system, it has to send message.
    //-------------------------------------------------------------------------

    /**
     * General handler to receive message coming from webkit thread
     */
    class PrivateHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
            // exclude INVAL_RECT_MSG_ID since it is frequently output
            if (DebugFlags.WEB_VIEW && msg.what != INVAL_RECT_MSG_ID) {
                if (msg.what >= FIRST_PRIVATE_MSG_ID
                        && msg.what <= LAST_PRIVATE_MSG_ID) {
                    Log.v(LOGTAG, HandlerPrivateDebugString[msg.what
                            - FIRST_PRIVATE_MSG_ID]);
                } else if (msg.what >= FIRST_PACKAGE_MSG_ID
                        && msg.what <= LAST_PACKAGE_MSG_ID) {
                    Log.v(LOGTAG, HandlerPackageDebugString[msg.what
                            - FIRST_PACKAGE_MSG_ID]);
                } else {
                    Log.v(LOGTAG, Integer.toString(msg.what));
                }
            }
            if (mWebViewCore == null) {
                // after WebView's destroy() is called, skip handling messages.
                return;
            }
            if (mBlockWebkitViewMessages
                    && msg.what != WEBCORE_INITIALIZED_MSG_ID) {
                // Blocking messages from webkit
                return;
            }
            switch (msg.what) {
                case REMEMBER_PASSWORD: {
                    mDatabase.setUsernamePassword(
                            msg.getData().getString("host"),
                            msg.getData().getString("username"),
                            msg.getData().getString("password"));
                    ((Message) msg.obj).sendToTarget();
                    break;
                }
                case NEVER_REMEMBER_PASSWORD: {
                    mDatabase.setUsernamePassword(
                            msg.getData().getString("host"), null, null);
                    ((Message) msg.obj).sendToTarget();
                    break;
                }
                case PREVENT_DEFAULT_TIMEOUT: {
                    // if timeout happens, cancel it so that it won't block UI
                    // to continue handling touch events
                    if ((msg.arg1 == MotionEvent.ACTION_DOWN
                            && mPreventDefault == PREVENT_DEFAULT_MAYBE_YES)
                            || (msg.arg1 == MotionEvent.ACTION_MOVE
                            && mPreventDefault == PREVENT_DEFAULT_NO_FROM_TOUCH_DOWN)) {
                        cancelWebCoreTouchEvent(
                                viewToContentX(mLastTouchX + mScrollX),
                                viewToContentY(mLastTouchY + mScrollY),
                                true);
                    }
                    break;
                }
                case SCROLL_SELECT_TEXT: {
                    if (mAutoScrollX == 0 && mAutoScrollY == 0) {
                        mSentAutoScrollMessage = false;
                        break;
                    }
                    if (mCurrentScrollingLayerId == 0) {
                        pinScrollBy(mAutoScrollX, mAutoScrollY, true, 0);
                    } else {
                        scrollLayerTo(mScrollingLayerRect.left + mAutoScrollX,
                                mScrollingLayerRect.top + mAutoScrollY);
                    }
                    sendEmptyMessageDelayed(
                            SCROLL_SELECT_TEXT, SELECT_SCROLL_INTERVAL);
                    break;
                }
                case UPDATE_SELECTION: {
                    if (mTouchMode == TOUCH_INIT_MODE
                            || mTouchMode == TOUCH_SHORTPRESS_MODE
                            || mTouchMode == TOUCH_SHORTPRESS_START_MODE) {
                        updateSelection();
                    }
                    break;
                }
                case SWITCH_TO_SHORTPRESS: {
                    if (mTouchMode == TOUCH_INIT_MODE) {
                        if (!sDisableNavcache
                                && mPreventDefault != PREVENT_DEFAULT_YES) {
                            mTouchMode = TOUCH_SHORTPRESS_START_MODE;
                            updateSelection();
                        } else {
                            // set to TOUCH_SHORTPRESS_MODE so that it won't
                            // trigger double tap any more
                            mTouchMode = TOUCH_SHORTPRESS_MODE;
                        }
                    } else if (mTouchMode == TOUCH_DOUBLE_TAP_MODE) {
                        mTouchMode = TOUCH_DONE_MODE;
                    }
                    break;
                }
                case SWITCH_TO_LONGPRESS: {
                    if (sDisableNavcache) {
                        removeTouchHighlight();
                    }
                    if (inFullScreenMode() || mDeferTouchProcess) {
                        TouchEventData ted = new TouchEventData();
                        ted.mAction = WebViewCore.ACTION_LONGPRESS;
                        ted.mIds = new int[1];
                        ted.mIds[0] = 0;
                        ted.mPoints = new Point[1];
                        ted.mPoints[0] = new Point(viewToContentX(mLastTouchX + mScrollX),
                                                   viewToContentY(mLastTouchY + mScrollY));
                        ted.mPointsInView = new Point[1];
                        ted.mPointsInView[0] = new Point(mLastTouchX, mLastTouchY);
                        // metaState for long press is tricky. Should it be the
                        // state when the press started or when the press was
                        // released? Or some intermediary key state? For
                        // simplicity for now, we don't set it.
                        ted.mMetaState = 0;
                        ted.mReprocess = mDeferTouchProcess;
                        ted.mNativeLayer = nativeScrollableLayer(
                                ted.mPoints[0].x, ted.mPoints[0].y,
                                ted.mNativeLayerRect, null);
                        ted.mSequence = mTouchEventQueue.nextTouchSequence();
                        mTouchEventQueue.preQueueTouchEventData(ted);
                        mWebViewCore.sendMessage(EventHub.TOUCH_EVENT, ted);
                    } else if (mPreventDefault != PREVENT_DEFAULT_YES) {
                        mTouchMode = TOUCH_DONE_MODE;
                        performLongClick();
                    }
                    break;
                }
                case RELEASE_SINGLE_TAP: {
                    doShortPress();
                    break;
                }
                case SCROLL_TO_MSG_ID: {
                    // arg1 = animate, arg2 = onlyIfImeIsShowing
                    // obj = Point(x, y)
                    if (msg.arg2 == 1) {
                        // This scroll is intended to bring the textfield into
                        // view, but is only necessary if the IME is showing
                        InputMethodManager imm = InputMethodManager.peekInstance();
                        if (imm == null || !imm.isAcceptingText()
                                || (!imm.isActive(WebView.this) && (!inEditingMode()
                                || !imm.isActive(mWebTextView)))) {
                            break;
                        }
                    }
                    final Point p = (Point) msg.obj;
                    if (msg.arg1 == 1) {
                        spawnContentScrollTo(p.x, p.y);
                    } else {
                        setContentScrollTo(p.x, p.y);
                    }
                    break;
                }
                case UPDATE_ZOOM_RANGE: {
                    WebViewCore.ViewState viewState = (WebViewCore.ViewState) msg.obj;
                    // mScrollX contains the new minPrefWidth
                    mZoomManager.updateZoomRange(viewState, getViewWidth(), viewState.mScrollX);
                    break;
                }
                case UPDATE_ZOOM_DENSITY: {
                    final float density = (Float) msg.obj;
                    mZoomManager.updateDefaultZoomDensity(density);
                    break;
                }
                case REPLACE_BASE_CONTENT: {
                    nativeReplaceBaseContent(msg.arg1);
                    break;
                }
                case NEW_PICTURE_MSG_ID: {
                    // called for new content
                    final WebViewCore.DrawData draw = (WebViewCore.DrawData) msg.obj;
                    setNewPicture(draw, true);
                    break;
                }
                case WEBCORE_INITIALIZED_MSG_ID:
                    // nativeCreate sets mNativeClass to a non-zero value
                    String drawableDir = BrowserFrame.getRawResFilename(
                            BrowserFrame.DRAWABLEDIR, mContext);
                    WindowManager windowManager =
                            (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
                    Display display = windowManager.getDefaultDisplay();
                    nativeCreate(msg.arg1, drawableDir,
                            ActivityManager.isHighEndGfx(display));
                    if (mDelaySetPicture != null) {
                        setNewPicture(mDelaySetPicture, true);
                        mDelaySetPicture = null;
                    }
                    if (mIsPaused) {
                        nativeSetPauseDrawing(mNativeClass, true);
                    }
                    break;
                case UPDATE_TEXTFIELD_TEXT_MSG_ID:
                    // Make sure that the textfield is currently focused
                    // and representing the same node as the pointer.
                    if (msg.arg2 == mTextGeneration) {
                        String text = (String) msg.obj;
                        if (null == text) {
                            text = "";
                        }
                        if (inEditingMode() &&
                                mWebTextView.isSameTextField(msg.arg1)) {
                            mWebTextView.setTextAndKeepSelection(text);
                        } else if (mInputConnection != null &&
                                mFieldPointer == msg.arg1) {
                            mInputConnection.setTextAndKeepSelection(text);
                        }
                    }
                    break;
                case REQUEST_KEYBOARD_WITH_SELECTION_MSG_ID:
                    displaySoftKeyboard(true);
                    // fall through to UPDATE_TEXT_SELECTION_MSG_ID
                case UPDATE_TEXT_SELECTION_MSG_ID:
                    updateTextSelectionFromMessage(msg.arg1, msg.arg2,
                            (WebViewCore.TextSelectionData) msg.obj);
                    break;
                case FORM_DID_BLUR:
                    if (inEditingMode()
                            && mWebTextView.isSameTextField(msg.arg1)) {
                        hideSoftKeyboard();
                    }
                    break;
                case RETURN_LABEL:
                    if (inEditingMode()
                            && mWebTextView.isSameTextField(msg.arg1)) {
                        mWebTextView.setHint((String) msg.obj);
                        InputMethodManager imm
                                = InputMethodManager.peekInstance();
                        // The hint is propagated to the IME in
                        // onCreateInputConnection.  If the IME is already
                        // active, restart it so that its hint text is updated.
                        if (imm != null && imm.isActive(mWebTextView)) {
                            imm.restartInput(mWebTextView);
                        }
                    }
                    break;
                case UNHANDLED_NAV_KEY:
                    navHandledKey(msg.arg1, 1, false, 0);
                    break;
                case UPDATE_TEXT_ENTRY_MSG_ID:
                    // this is sent after finishing resize in WebViewCore. Make
                    // sure the text edit box is still on the  screen.
                    if (inEditingMode() && nativeCursorIsTextInput()) {
                        updateWebTextViewPosition();
                    }
                    break;
                case CLEAR_TEXT_ENTRY:
                    clearTextEntry();
                    break;
                case INVAL_RECT_MSG_ID: {
                    Rect r = (Rect)msg.obj;
                    if (r == null) {
                        invalidate();
                    } else {
                        // we need to scale r from content into view coords,
                        // which viewInvalidate() does for us
                        viewInvalidate(r.left, r.top, r.right, r.bottom);
                    }
                    break;
                }
                case REQUEST_FORM_DATA:
                    AutoCompleteAdapter adapter = (AutoCompleteAdapter) msg.obj;
                    if (mWebTextView.isSameTextField(msg.arg1)) {
                        mWebTextView.setAdapterCustom(adapter);
                    }
                    break;

                case LONG_PRESS_CENTER:
                    // as this is shared by keydown and trackballdown, reset all
                    // the states
                    mGotCenterDown = false;
                    mTrackballDown = false;
                    performLongClick();
                    break;

                case WEBCORE_NEED_TOUCH_EVENTS:
                    mForwardTouchEvents = (msg.arg1 != 0);
                    break;

                case PREVENT_TOUCH_ID:
                    if (inFullScreenMode()) {
                        break;
                    }
                    TouchEventData ted = (TouchEventData) msg.obj;

                    if (mTouchEventQueue.enqueueTouchEvent(ted)) {
                        // WebCore is responding to us; remove pending timeout.
                        // It will be re-posted when needed.
                        removeMessages(PREVENT_DEFAULT_TIMEOUT);
                    }
                    break;

                case REQUEST_KEYBOARD:
                    if (msg.arg1 == 0) {
                        hideSoftKeyboard();
                    } else {
                        displaySoftKeyboard(false);
                    }
                    break;

                case FIND_AGAIN:
                    // Ignore if find has been dismissed.
                    if (mFindIsUp && mFindCallback != null) {
                        mFindCallback.findAll();
                    }
                    break;

                case DRAG_HELD_MOTIONLESS:
                    mHeldMotionless = MOTIONLESS_TRUE;
                    invalidate();
                    // fall through to keep scrollbars awake

                case AWAKEN_SCROLL_BARS:
                    if (mTouchMode == TOUCH_DRAG_MODE
                            && mHeldMotionless == MOTIONLESS_TRUE) {
                        awakenScrollBars(ViewConfiguration
                                .getScrollDefaultDelay(), false);
                        mPrivateHandler.sendMessageDelayed(mPrivateHandler
                                .obtainMessage(AWAKEN_SCROLL_BARS),
                                ViewConfiguration.getScrollDefaultDelay());
                    }
                    break;

                case DO_MOTION_UP:
                    doMotionUp(msg.arg1, msg.arg2);
                    break;

                case SCREEN_ON:
                    setKeepScreenOn(msg.arg1 == 1);
                    break;

                case ENTER_FULLSCREEN_VIDEO:
                    int layerId = msg.arg1;

                    String url = (String) msg.obj;
                    if (mHTML5VideoViewProxy != null) {
                        mHTML5VideoViewProxy.enterFullScreenVideo(layerId, url);
                    }
                    break;

                case EXIT_FULLSCREEN_VIDEO:
                    if (mHTML5VideoViewProxy != null) {
                        mHTML5VideoViewProxy.exitFullScreenVideo();
                    }
                    break;

                case SHOW_FULLSCREEN: {
                    View view = (View) msg.obj;
                    int orientation = msg.arg1;
                    int npp = msg.arg2;

                    if (inFullScreenMode()) {
                        Log.w(LOGTAG, "Should not have another full screen.");
                        dismissFullScreenMode();
                    }
                    mFullScreenHolder = new PluginFullScreenHolder(WebView.this, orientation, npp);
                    mFullScreenHolder.setContentView(view);
                    mFullScreenHolder.show();
                    invalidate();

                    break;
                }
                case HIDE_FULLSCREEN:
                    dismissFullScreenMode();
                    break;

                case DOM_FOCUS_CHANGED:
                    if (inEditingMode()) {
                        nativeClearCursor();
                        rebuildWebTextView();
                    }
                    break;

                case SHOW_RECT_MSG_ID: {
                    WebViewCore.ShowRectData data = (WebViewCore.ShowRectData) msg.obj;
                    int x = mScrollX;
                    int left = contentToViewX(data.mLeft);
                    int width = contentToViewDimension(data.mWidth);
                    int maxWidth = contentToViewDimension(data.mContentWidth);
                    int viewWidth = getViewWidth();
                    if (width < viewWidth) {
                        // center align
                        x += left + width / 2 - mScrollX - viewWidth / 2;
                    } else {
                        x += (int) (left + data.mXPercentInDoc * width
                                - mScrollX - data.mXPercentInView * viewWidth);
                    }
                    if (DebugFlags.WEB_VIEW) {
                        Log.v(LOGTAG, "showRectMsg=(left=" + left + ",width=" +
                              width + ",maxWidth=" + maxWidth +
                              ",viewWidth=" + viewWidth + ",x="
                              + x + ",xPercentInDoc=" + data.mXPercentInDoc +
                              ",xPercentInView=" + data.mXPercentInView+ ")");
                    }
                    // use the passing content width to cap x as the current
                    // mContentWidth may not be updated yet
                    x = Math.max(0,
                            (Math.min(maxWidth, x + viewWidth)) - viewWidth);
                    int top = contentToViewY(data.mTop);
                    int height = contentToViewDimension(data.mHeight);
                    int maxHeight = contentToViewDimension(data.mContentHeight);
                    int viewHeight = getViewHeight();
                    int y = (int) (top + data.mYPercentInDoc * height -
                                   data.mYPercentInView * viewHeight);
                    if (DebugFlags.WEB_VIEW) {
                        Log.v(LOGTAG, "showRectMsg=(top=" + top + ",height=" +
                              height + ",maxHeight=" + maxHeight +
                              ",viewHeight=" + viewHeight + ",y="
                              + y + ",yPercentInDoc=" + data.mYPercentInDoc +
                              ",yPercentInView=" + data.mYPercentInView+ ")");
                    }
                    // use the passing content height to cap y as the current
                    // mContentHeight may not be updated yet
                    y = Math.max(0,
                            (Math.min(maxHeight, y + viewHeight) - viewHeight));
                    // We need to take into account the visible title height
                    // when scrolling since y is an absolute view position.
                    y = Math.max(0, y - getVisibleTitleHeightImpl());
                    scrollTo(x, y);
                    }
                    break;

                case CENTER_FIT_RECT:
                    centerFitRect((Rect)msg.obj);
                    break;

                case SET_SCROLLBAR_MODES:
                    mHorizontalScrollBarMode = msg.arg1;
                    mVerticalScrollBarMode = msg.arg2;
                    break;

                case SELECTION_STRING_CHANGED:
                    if (mAccessibilityInjector != null) {
                        String selectionString = (String) msg.obj;
                        mAccessibilityInjector.onSelectionStringChange(selectionString);
                    }
                    break;

                case HIT_TEST_RESULT:
                    WebKitHitTest hit = (WebKitHitTest) msg.obj;
                    mFocusedNode = hit;
                    setTouchHighlightRects(hit);
                    if (hit == null) {
                        mInitialHitTestResult = null;
                    } else {
                        mInitialHitTestResult = new HitTestResult();
                        if (hit.mLinkUrl != null) {
                            mInitialHitTestResult.mType = HitTestResult.SRC_ANCHOR_TYPE;
                            mInitialHitTestResult.mExtra = hit.mLinkUrl;
                            if (hit.mImageUrl != null) {
                                mInitialHitTestResult.mType = HitTestResult.SRC_IMAGE_ANCHOR_TYPE;
                                mInitialHitTestResult.mExtra = hit.mImageUrl;
                            }
                        } else if (hit.mImageUrl != null) {
                            mInitialHitTestResult.mType = HitTestResult.IMAGE_TYPE;
                            mInitialHitTestResult.mExtra = hit.mImageUrl;
                        } else if (hit.mEditable) {
                            mInitialHitTestResult.mType = HitTestResult.EDIT_TEXT_TYPE;
                        }
                    }
                    break;

                case SAVE_WEBARCHIVE_FINISHED:
                    SaveWebArchiveMessage saveMessage = (SaveWebArchiveMessage)msg.obj;
                    if (saveMessage.mCallback != null) {
                        saveMessage.mCallback.onReceiveValue(saveMessage.mResultFile);
                    }
                    break;

                case SET_AUTOFILLABLE:
                    mAutoFillData = (WebViewCore.AutoFillData) msg.obj;
                    if (mWebTextView != null) {
                        mWebTextView.setAutoFillable(mAutoFillData.getQueryId());
                        rebuildWebTextView();
                    }
                    break;

                case AUTOFILL_COMPLETE:
                    if (mWebTextView != null) {
                        // Clear the WebTextView adapter when AutoFill finishes
                        // so that the drop down gets cleared.
                        mWebTextView.setAdapterCustom(null);
                    }
                    break;

                case SELECT_AT:
                    nativeSelectAt(msg.arg1, msg.arg2);
                    break;

                case COPY_TO_CLIPBOARD:
                    copyToClipboard((String) msg.obj);
                    break;

                case INIT_EDIT_FIELD:
                    if (mInputConnection != null) {
                        mTextGeneration = 0;
                        mFieldPointer = msg.arg1;
                        mInputConnection.setTextAndKeepSelection((String) msg.obj);
                    }
                    break;

                case REPLACE_TEXT:{
                    String text = (String)msg.obj;
                    int start = msg.arg1;
                    int end = msg.arg2;
                    int cursorPosition = start + text.length();
                    replaceTextfieldText(start, end, text,
                            cursorPosition, cursorPosition);
                    break;
                }

                default:
                    super.handleMessage(msg);
                    break;
            }
        }
    }

    private void setTouchHighlightRects(WebKitHitTest hit) {
        Rect[] rects = hit != null ? hit.mTouchRects : null;
        if (!mTouchHighlightRegion.isEmpty()) {
            invalidate(mTouchHighlightRegion.getBounds());
            mTouchHighlightRegion.setEmpty();
        }
        if (rects != null) {
            mTouchHightlightPaint.setColor(hit.mTapHighlightColor);
            for (Rect rect : rects) {
                Rect viewRect = contentToViewRect(rect);
                // some sites, like stories in nytimes.com, set
                // mouse event handler in the top div. It is not
                // user friendly to highlight the div if it covers
                // more than half of the screen.
                if (viewRect.width() < getWidth() >> 1
                        || viewRect.height() < getHeight() >> 1) {
                    mTouchHighlightRegion.union(viewRect);
                } else {
                    Log.w(LOGTAG, "Skip the huge selection rect:"
                            + viewRect);
                }
            }
            invalidate(mTouchHighlightRegion.getBounds());
        }
    }

    /** @hide Called by JNI when pages are swapped (only occurs with hardware
     * acceleration) */
    protected void pageSwapCallback(boolean notifyAnimationStarted) {
        mWebViewCore.resumeWebKitDraw();
        if (inEditingMode()) {
            didUpdateWebTextViewDimensions(ANYWHERE);
        }
        if (notifyAnimationStarted) {
            mWebViewCore.sendMessage(EventHub.NOTIFY_ANIMATION_STARTED);
        }
    }

    void setNewPicture(final WebViewCore.DrawData draw, boolean updateBaseLayer) {
        if (mNativeClass == 0) {
            if (mDelaySetPicture != null) {
                throw new IllegalStateException("Tried to setNewPicture with"
                        + " a delay picture already set! (memory leak)");
            }
            // Not initialized yet, delay set
            mDelaySetPicture = draw;
            return;
        }
        WebViewCore.ViewState viewState = draw.mViewState;
        boolean isPictureAfterFirstLayout = viewState != null;

        if (updateBaseLayer) {
            setBaseLayer(draw.mBaseLayer, draw.mInvalRegion,
                    getSettings().getShowVisualIndicator(),
                    isPictureAfterFirstLayout);
        }
        final Point viewSize = draw.mViewSize;
        // We update the layout (i.e. request a layout from the
        // view system) if the last view size that we sent to
        // WebCore matches the view size of the picture we just
        // received in the fixed dimension.
        final boolean updateLayout = viewSize.x == mLastWidthSent
                && viewSize.y == mLastHeightSent;
        // Don't send scroll event for picture coming from webkit,
        // since the new picture may cause a scroll event to override
        // the saved history scroll position.
        mSendScrollEvent = false;
        recordNewContentSize(draw.mContentSize.x,
                draw.mContentSize.y, updateLayout);
        if (isPictureAfterFirstLayout) {
            // Reset the last sent data here since dealing with new page.
            mLastWidthSent = 0;
            mZoomManager.onFirstLayout(draw);
            int scrollX = viewState.mShouldStartScrolledRight
                    ? getContentWidth() : viewState.mScrollX;
            int scrollY = viewState.mScrollY;
            setContentScrollTo(scrollX, scrollY);
            if (!mDrawHistory) {
                // As we are on a new page, remove the WebTextView. This
                // is necessary for page loads driven by webkit, and in
                // particular when the user was on a password field, so
                // the WebTextView was visible.
                clearTextEntry();
            }
        }
        mSendScrollEvent = true;

        if (DebugFlags.WEB_VIEW) {
            Rect b = draw.mInvalRegion.getBounds();
            Log.v(LOGTAG, "NEW_PICTURE_MSG_ID {" +
                    b.left+","+b.top+","+b.right+","+b.bottom+"}");
        }
        invalidateContentRect(draw.mInvalRegion.getBounds());

        if (mPictureListener != null) {
            mPictureListener.onNewPicture(WebView.this, capturePicture());
        }

        // update the zoom information based on the new picture
        mZoomManager.onNewPicture(draw);

        if (draw.mFocusSizeChanged && inEditingMode()) {
            mFocusSizeChanged = true;
        }
        if (isPictureAfterFirstLayout) {
            mViewManager.postReadyToDrawAll();
        }
    }

    /**
     * Used when receiving messages for REQUEST_KEYBOARD_WITH_SELECTION_MSG_ID
     * and UPDATE_TEXT_SELECTION_MSG_ID.  Update the selection of WebTextView.
     */
    private void updateTextSelectionFromMessage(int nodePointer,
            int textGeneration, WebViewCore.TextSelectionData data) {
        if (textGeneration == mTextGeneration) {
            if (inEditingMode()
                    && mWebTextView.isSameTextField(nodePointer)) {
                mWebTextView.setSelectionFromWebKit(data.mStart, data.mEnd);
            } else if (mInputConnection != null && mFieldPointer == nodePointer) {
                mInputConnection.setSelection(data.mStart, data.mEnd);
            }
        }

        nativeSetTextSelection(mNativeClass, data.mSelectTextPtr);
        if (data.mSelectTextPtr != 0) {
            if (!mSelectingText) {
                setupWebkitSelect();
            } else if (!mSelectionStarted) {
                syncSelectionCursors();
            }
        } else {
            selectionDone();
        }
        invalidate();
    }

    // Class used to use a dropdown for a <select> element
    private class InvokeListBox implements Runnable {
        // Whether the listbox allows multiple selection.
        private boolean     mMultiple;
        // Passed in to a list with multiple selection to tell
        // which items are selected.
        private int[]       mSelectedArray;
        // Passed in to a list with single selection to tell
        // where the initial selection is.
        private int         mSelection;

        private Container[] mContainers;

        // Need these to provide stable ids to my ArrayAdapter,
        // which normally does not have stable ids. (Bug 1250098)
        private class Container extends Object {
            /**
             * Possible values for mEnabled.  Keep in sync with OptionStatus in
             * WebViewCore.cpp
             */
            final static int OPTGROUP = -1;
            final static int OPTION_DISABLED = 0;
            final static int OPTION_ENABLED = 1;

            String  mString;
            int     mEnabled;
            int     mId;

            @Override
            public String toString() {
                return mString;
            }
        }

        /**
         *  Subclass ArrayAdapter so we can disable OptionGroupLabels,
         *  and allow filtering.
         */
        private class MyArrayListAdapter extends ArrayAdapter<Container> {
            public MyArrayListAdapter() {
                super(mContext,
                        mMultiple ? com.android.internal.R.layout.select_dialog_multichoice :
                        com.android.internal.R.layout.webview_select_singlechoice,
                        mContainers);
            }

            @Override
            public View getView(int position, View convertView,
                    ViewGroup parent) {
                // Always pass in null so that we will get a new CheckedTextView
                // Otherwise, an item which was previously used as an <optgroup>
                // element (i.e. has no check), could get used as an <option>
                // element, which needs a checkbox/radio, but it would not have
                // one.
                convertView = super.getView(position, null, parent);
                Container c = item(position);
                if (c != null && Container.OPTION_ENABLED != c.mEnabled) {
                    // ListView does not draw dividers between disabled and
                    // enabled elements.  Use a LinearLayout to provide dividers
                    LinearLayout layout = new LinearLayout(mContext);
                    layout.setOrientation(LinearLayout.VERTICAL);
                    if (position > 0) {
                        View dividerTop = new View(mContext);
                        dividerTop.setBackgroundResource(
                                android.R.drawable.divider_horizontal_bright);
                        layout.addView(dividerTop);
                    }

                    if (Container.OPTGROUP == c.mEnabled) {
                        // Currently select_dialog_multichoice uses CheckedTextViews.
                        // If that changes, the class cast will no longer be valid.
                        if (mMultiple) {
                            Assert.assertTrue(convertView instanceof CheckedTextView);
                            ((CheckedTextView) convertView).setCheckMarkDrawable(null);
                        }
                    } else {
                        // c.mEnabled == Container.OPTION_DISABLED
                        // Draw the disabled element in a disabled state.
                        convertView.setEnabled(false);
                    }

                    layout.addView(convertView);
                    if (position < getCount() - 1) {
                        View dividerBottom = new View(mContext);
                        dividerBottom.setBackgroundResource(
                                android.R.drawable.divider_horizontal_bright);
                        layout.addView(dividerBottom);
                    }
                    return layout;
                }
                return convertView;
            }

            @Override
            public boolean hasStableIds() {
                // AdapterView's onChanged method uses this to determine whether
                // to restore the old state.  Return false so that the old (out
                // of date) state does not replace the new, valid state.
                return false;
            }

            private Container item(int position) {
                if (position < 0 || position >= getCount()) {
                    return null;
                }
                return getItem(position);
            }

            @Override
            public long getItemId(int position) {
                Container item = item(position);
                if (item == null) {
                    return -1;
                }
                return item.mId;
            }

            @Override
            public boolean areAllItemsEnabled() {
                return false;
            }

            @Override
            public boolean isEnabled(int position) {
                Container item = item(position);
                if (item == null) {
                    return false;
                }
                return Container.OPTION_ENABLED == item.mEnabled;
            }
        }

        private InvokeListBox(String[] array, int[] enabled, int[] selected) {
            mMultiple = true;
            mSelectedArray = selected;

            int length = array.length;
            mContainers = new Container[length];
            for (int i = 0; i < length; i++) {
                mContainers[i] = new Container();
                mContainers[i].mString = array[i];
                mContainers[i].mEnabled = enabled[i];
                mContainers[i].mId = i;
            }
        }

        private InvokeListBox(String[] array, int[] enabled, int selection) {
            mSelection = selection;
            mMultiple = false;

            int length = array.length;
            mContainers = new Container[length];
            for (int i = 0; i < length; i++) {
                mContainers[i] = new Container();
                mContainers[i].mString = array[i];
                mContainers[i].mEnabled = enabled[i];
                mContainers[i].mId = i;
            }
        }

        /*
         * Whenever the data set changes due to filtering, this class ensures
         * that the checked item remains checked.
         */
        private class SingleDataSetObserver extends DataSetObserver {
            private long        mCheckedId;
            private ListView    mListView;
            private Adapter     mAdapter;

            /*
             * Create a new observer.
             * @param id The ID of the item to keep checked.
             * @param l ListView for getting and clearing the checked states
             * @param a Adapter for getting the IDs
             */
            public SingleDataSetObserver(long id, ListView l, Adapter a) {
                mCheckedId = id;
                mListView = l;
                mAdapter = a;
            }

            @Override
            public void onChanged() {
                // The filter may have changed which item is checked.  Find the
                // item that the ListView thinks is checked.
                int position = mListView.getCheckedItemPosition();
                long id = mAdapter.getItemId(position);
                if (mCheckedId != id) {
                    // Clear the ListView's idea of the checked item, since
                    // it is incorrect
                    mListView.clearChoices();
                    // Search for mCheckedId.  If it is in the filtered list,
                    // mark it as checked
                    int count = mAdapter.getCount();
                    for (int i = 0; i < count; i++) {
                        if (mAdapter.getItemId(i) == mCheckedId) {
                            mListView.setItemChecked(i, true);
                            break;
                        }
                    }
                }
            }
        }

        @Override
        public void run() {
            final ListView listView = (ListView) LayoutInflater.from(mContext)
                    .inflate(com.android.internal.R.layout.select_dialog, null);
            final MyArrayListAdapter adapter = new MyArrayListAdapter();
            AlertDialog.Builder b = new AlertDialog.Builder(mContext)
                    .setView(listView).setCancelable(true)
                    .setInverseBackgroundForced(true);

            if (mMultiple) {
                b.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        mWebViewCore.sendMessage(
                                EventHub.LISTBOX_CHOICES,
                                adapter.getCount(), 0,
                                listView.getCheckedItemPositions());
                    }});
                b.setNegativeButton(android.R.string.cancel,
                        new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        mWebViewCore.sendMessage(
                                EventHub.SINGLE_LISTBOX_CHOICE, -2, 0);
                }});
            }
            mListBoxDialog = b.create();
            listView.setAdapter(adapter);
            listView.setFocusableInTouchMode(true);
            // There is a bug (1250103) where the checks in a ListView with
            // multiple items selected are associated with the positions, not
            // the ids, so the items do not properly retain their checks when
            // filtered.  Do not allow filtering on multiple lists until
            // that bug is fixed.

            listView.setTextFilterEnabled(!mMultiple);
            if (mMultiple) {
                listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
                int length = mSelectedArray.length;
                for (int i = 0; i < length; i++) {
                    listView.setItemChecked(mSelectedArray[i], true);
                }
            } else {
                listView.setOnItemClickListener(new OnItemClickListener() {
                    @Override
                    public void onItemClick(AdapterView<?> parent, View v,
                            int position, long id) {
                        // Rather than sending the message right away, send it
                        // after the page regains focus.
                        mListBoxMessage = Message.obtain(null,
                                EventHub.SINGLE_LISTBOX_CHOICE, (int) id, 0);
                        mListBoxDialog.dismiss();
                        mListBoxDialog = null;
                    }
                });
                if (mSelection != -1) {
                    listView.setSelection(mSelection);
                    listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
                    listView.setItemChecked(mSelection, true);
                    DataSetObserver observer = new SingleDataSetObserver(
                            adapter.getItemId(mSelection), listView, adapter);
                    adapter.registerDataSetObserver(observer);
                }
            }
            mListBoxDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
                @Override
                public void onCancel(DialogInterface dialog) {
                    mWebViewCore.sendMessage(
                                EventHub.SINGLE_LISTBOX_CHOICE, -2, 0);
                    mListBoxDialog = null;
                }
            });
            mListBoxDialog.show();
        }
    }

    private Message mListBoxMessage;

    /*
     * Request a dropdown menu for a listbox with multiple selection.
     *
     * @param array Labels for the listbox.
     * @param enabledArray  State for each element in the list.  See static
     *      integers in Container class.
     * @param selectedArray Which positions are initally selected.
     */
    void requestListBox(String[] array, int[] enabledArray, int[]
            selectedArray) {
        mPrivateHandler.post(
                new InvokeListBox(array, enabledArray, selectedArray));
    }

    /*
     * Request a dropdown menu for a listbox with single selection or a single
     * <select> element.
     *
     * @param array Labels for the listbox.
     * @param enabledArray  State for each element in the list.  See static
     *      integers in Container class.
     * @param selection Which position is initally selected.
     */
    void requestListBox(String[] array, int[] enabledArray, int selection) {
        mPrivateHandler.post(
                new InvokeListBox(array, enabledArray, selection));
    }

    // called by JNI
    private void sendMoveFocus(int frame, int node) {
        mWebViewCore.sendMessage(EventHub.SET_MOVE_FOCUS,
                new WebViewCore.CursorData(frame, node, 0, 0));
    }

    // called by JNI
    private void sendMoveMouse(int frame, int node, int x, int y) {
        mWebViewCore.sendMessage(EventHub.SET_MOVE_MOUSE,
                new WebViewCore.CursorData(frame, node, x, y));
    }

    /*
     * Send a mouse move event to the webcore thread.
     *
     * @param removeFocus Pass true to remove the WebTextView, if present.
     * @param stopPaintingCaret Stop drawing the blinking caret if true.
     * called by JNI
     */
    @SuppressWarnings("unused")
    private void sendMoveMouseIfLatest(boolean removeFocus, boolean stopPaintingCaret) {
        if (removeFocus) {
            clearTextEntry();
        }
        mWebViewCore.sendMessage(EventHub.SET_MOVE_MOUSE_IF_LATEST,
                stopPaintingCaret ? 1 : 0, 0,
                cursorData());
    }

    /**
     * Called by JNI to send a message to the webcore thread that the user
     * touched the webpage.
     * @param touchGeneration Generation number of the touch, to ignore touches
     *      after a new one has been generated.
     * @param frame Pointer to the frame holding the node that was touched.
     * @param node Pointer to the node touched.
     * @param x x-position of the touch.
     * @param y y-position of the touch.
     */
    private void sendMotionUp(int touchGeneration,
            int frame, int node, int x, int y) {
        WebViewCore.TouchUpData touchUpData = new WebViewCore.TouchUpData();
        touchUpData.mMoveGeneration = touchGeneration;
        touchUpData.mFrame = frame;
        touchUpData.mNode = node;
        touchUpData.mX = x;
        touchUpData.mY = y;
        touchUpData.mNativeLayer = nativeScrollableLayer(
                x, y, touchUpData.mNativeLayerRect, null);
        mWebViewCore.sendMessage(EventHub.TOUCH_UP, touchUpData);
    }


    private int getScaledMaxXScroll() {
        int width;
        if (mHeightCanMeasure == false) {
            width = getViewWidth() / 4;
        } else {
            Rect visRect = new Rect();
            calcOurVisibleRect(visRect);
            width = visRect.width() / 2;
        }
        // FIXME the divisor should be retrieved from somewhere
        return viewToContentX(width);
    }

    private int getScaledMaxYScroll() {
        int height;
        if (mHeightCanMeasure == false) {
            height = getViewHeight() / 4;
        } else {
            Rect visRect = new Rect();
            calcOurVisibleRect(visRect);
            height = visRect.height() / 2;
        }
        // FIXME the divisor should be retrieved from somewhere
        // the closest thing today is hard-coded into ScrollView.java
        // (from ScrollView.java, line 363)   int maxJump = height/2;
        return Math.round(height * mZoomManager.getInvScale());
    }

    /**
     * Called by JNI to invalidate view
     */
    private void viewInvalidate() {
        invalidate();
    }

    /**
     * Pass the key directly to the page.  This assumes that
     * nativePageShouldHandleShiftAndArrows() returned true.
     */
    private void letPageHandleNavKey(int keyCode, long time, boolean down, int metaState) {
        int keyEventAction;
        int eventHubAction;
        if (down) {
            keyEventAction = KeyEvent.ACTION_DOWN;
            eventHubAction = EventHub.KEY_DOWN;
            playSoundEffect(keyCodeToSoundsEffect(keyCode));
        } else {
            keyEventAction = KeyEvent.ACTION_UP;
            eventHubAction = EventHub.KEY_UP;
        }

        KeyEvent event = new KeyEvent(time, time, keyEventAction, keyCode,
                1, (metaState & KeyEvent.META_SHIFT_ON)
                | (metaState & KeyEvent.META_ALT_ON)
                | (metaState & KeyEvent.META_SYM_ON)
                , KeyCharacterMap.VIRTUAL_KEYBOARD, 0, 0);
        mWebViewCore.sendMessage(eventHubAction, event);
    }

    // return true if the key was handled
    private boolean navHandledKey(int keyCode, int count, boolean noScroll,
            long time) {
        if (mNativeClass == 0) {
            return false;
        }
        mInitialHitTestResult = null;
        mLastCursorTime = time;
        mLastCursorBounds = nativeGetCursorRingBounds();
        boolean keyHandled
                = nativeMoveCursor(keyCode, count, noScroll) == false;
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "navHandledKey mLastCursorBounds=" + mLastCursorBounds
                    + " mLastCursorTime=" + mLastCursorTime
                    + " handled=" + keyHandled);
        }
        if (keyHandled == false) {
            return keyHandled;
        }
        Rect contentCursorRingBounds = nativeGetCursorRingBounds();
        if (contentCursorRingBounds.isEmpty()) return keyHandled;
        Rect viewCursorRingBounds = contentToViewRect(contentCursorRingBounds);
        // set last touch so that context menu related functions will work
        mLastTouchX = (viewCursorRingBounds.left + viewCursorRingBounds.right) / 2;
        mLastTouchY = (viewCursorRingBounds.top + viewCursorRingBounds.bottom) / 2;
        if (mHeightCanMeasure == false) {
            return keyHandled;
        }
        Rect visRect = new Rect();
        calcOurVisibleRect(visRect);
        Rect outset = new Rect(visRect);
        int maxXScroll = visRect.width() / 2;
        int maxYScroll = visRect.height() / 2;
        outset.inset(-maxXScroll, -maxYScroll);
        if (Rect.intersects(outset, viewCursorRingBounds) == false) {
            return keyHandled;
        }
        // FIXME: Necessary because ScrollView/ListView do not scroll left/right
        int maxH = Math.min(viewCursorRingBounds.right - visRect.right,
                maxXScroll);
        if (maxH > 0) {
            pinScrollBy(maxH, 0, true, 0);
        } else {
            maxH = Math.max(viewCursorRingBounds.left - visRect.left,
                    -maxXScroll);
            if (maxH < 0) {
                pinScrollBy(maxH, 0, true, 0);
            }
        }
        if (mLastCursorBounds.isEmpty()) return keyHandled;
        if (mLastCursorBounds.equals(contentCursorRingBounds)) {
            return keyHandled;
        }
        if (DebugFlags.WEB_VIEW) {
            Log.v(LOGTAG, "navHandledKey contentCursorRingBounds="
                    + contentCursorRingBounds);
        }
        requestRectangleOnScreen(viewCursorRingBounds);
        return keyHandled;
    }

    /**
     * @return Whether accessibility script has been injected.
     */
    private boolean accessibilityScriptInjected() {
        // TODO: Maybe the injected script should announce its presence in
        // the page meta-tag so the nativePageShouldHandleShiftAndArrows
        // will check that as one of the conditions it looks for
        return mAccessibilityScriptInjected;
    }

    /**
     * Set the background color. It's white by default. Pass
     * zero to make the view transparent.
     * @param color   the ARGB color described by Color.java
     */
    @Override
    public void setBackgroundColor(int color) {
        mBackgroundColor = color;
        mWebViewCore.sendMessage(EventHub.SET_BACKGROUND_COLOR, color);
    }

    /**
     * @deprecated This method is now obsolete.
     */
    @Deprecated
    public void debugDump() {
        checkThread();
        nativeDebugDump();
        mWebViewCore.sendMessage(EventHub.DUMP_NAVTREE);
    }

    /**
     * Draw the HTML page into the specified canvas. This call ignores any
     * view-specific zoom, scroll offset, or other changes. It does not draw
     * any view-specific chrome, such as progress or URL bars.
     *
     * @hide only needs to be accessible to Browser and testing
     */
    public void drawPage(Canvas canvas) {
        calcOurContentVisibleRectF(mVisibleContentRect);
        nativeDraw(canvas, mVisibleContentRect, 0, 0, false);
    }

    /**
     * Enable the communication b/t the webView and VideoViewProxy
     *
     * @hide only used by the Browser
     */
    public void setHTML5VideoViewProxy(HTML5VideoViewProxy proxy) {
        mHTML5VideoViewProxy = proxy;
    }

    /**
     * Set the time to wait between passing touches to WebCore. See also the
     * TOUCH_SENT_INTERVAL member for further discussion.
     *
     * @hide This is only used by the DRT test application.
     */
    public void setTouchInterval(int interval) {
        mCurrentTouchInterval = interval;
    }

    /**
     * Copy text into the clipboard. This is called indirectly from
     * WebViewCore.
     * @param text The text to put into the clipboard.
     */
    private void copyToClipboard(String text) {
        ClipboardManager cm = (ClipboardManager)getContext()
                .getSystemService(Context.CLIPBOARD_SERVICE);
        ClipData clip = ClipData.newPlainText(getTitle(), text);
        cm.setPrimaryClip(clip);
    }

    /**
     *  Update our cache with updatedText.
     *  @param updatedText  The new text to put in our cache.
     *  @hide
     */
    protected void updateCachedTextfield(String updatedText) {
        // Also place our generation number so that when we look at the cache
        // we recognize that it is up to date.
        nativeUpdateCachedTextfield(updatedText, mTextGeneration);
    }

    /*package*/ void autoFillForm(int autoFillQueryId) {
        mWebViewCore.sendMessage(EventHub.AUTOFILL_FORM, autoFillQueryId, /* unused */0);
    }

    /* package */ ViewManager getViewManager() {
        return mViewManager;
    }

    private static void checkThread() {
        if (Looper.myLooper() != Looper.getMainLooper()) {
            Throwable throwable = new Throwable(
                    "Warning: A WebView method was called on thread '" +
                    Thread.currentThread().getName() + "'. " +
                    "All WebView methods must be called on the UI thread. " +
                    "Future versions of WebView may not support use on other threads.");
            Log.w(LOGTAG, Log.getStackTraceString(throwable));
            StrictMode.onWebViewMethodCalledOnWrongThread(throwable);
        }
    }

    /** @hide send content invalidate */
    protected void contentInvalidateAll() {
        if (mWebViewCore != null && !mBlockWebkitViewMessages) {
            mWebViewCore.sendMessage(EventHub.CONTENT_INVALIDATE_ALL);
        }
    }

    /** @hide discard all textures from tiles */
    protected void discardAllTextures() {
        nativeDiscardAllTextures();
    }

    /**
     * Begin collecting per-tile profiling data
     *
     * @hide only used by profiling tests
     */
    public void tileProfilingStart() {
        nativeTileProfilingStart();
    }
    /**
     * Return per-tile profiling data
     *
     * @hide only used by profiling tests
     */
    public float tileProfilingStop() {
        return nativeTileProfilingStop();
    }

    /** @hide only used by profiling tests */
    public void tileProfilingClear() {
        nativeTileProfilingClear();
    }
    /** @hide only used by profiling tests */
    public int tileProfilingNumFrames() {
        return nativeTileProfilingNumFrames();
    }
    /** @hide only used by profiling tests */
    public int tileProfilingNumTilesInFrame(int frame) {
        return nativeTileProfilingNumTilesInFrame(frame);
    }
    /** @hide only used by profiling tests */
    public int tileProfilingGetInt(int frame, int tile, String key) {
        return nativeTileProfilingGetInt(frame, tile, key);
    }
    /** @hide only used by profiling tests */
    public float tileProfilingGetFloat(int frame, int tile, String key) {
        return nativeTileProfilingGetFloat(frame, tile, key);
    }

    /**
     * Checks the focused content for an editable text field. This can be
     * text input or ContentEditable.
     * @return true if the focused item is an editable text field.
     */
    boolean focusCandidateIsEditableText() {
        boolean isEditable = false;
        // TODO: reverse sDisableNavcache so that its name is positive
        boolean isNavcacheEnabled = !sDisableNavcache;
        if (isNavcacheEnabled) {
            isEditable = nativeFocusCandidateIsEditableText(mNativeClass);
        } else if (mFocusedNode != null) {
            isEditable = mFocusedNode.mEditable;
        }
        return isEditable;
    }

    private native int nativeCacheHitFramePointer();
    private native boolean  nativeCacheHitIsPlugin();
    private native Rect nativeCacheHitNodeBounds();
    private native int nativeCacheHitNodePointer();
    /* package */ native void nativeClearCursor();
    private native void     nativeCreate(int ptr, String drawableDir, boolean isHighEndGfx);
    private native int      nativeCursorFramePointer();
    private native Rect     nativeCursorNodeBounds();
    private native int nativeCursorNodePointer();
    private native boolean  nativeCursorIntersects(Rect visibleRect);
    private native boolean  nativeCursorIsAnchor();
    private native boolean  nativeCursorIsTextInput();
    private native Point    nativeCursorPosition();
    private native String   nativeCursorText();
    /**
     * Returns true if the native cursor node says it wants to handle key events
     * (ala plugins). This can only be called if mNativeClass is non-zero!
     */
    private native boolean  nativeCursorWantsKeyEvents();
    private native void     nativeDebugDump();
    private native void     nativeDestroy();

    /**
     * Draw the picture set with a background color and extra. If
     * "splitIfNeeded" is true and the return value is not 0, the return value
     * MUST be passed to WebViewCore with SPLIT_PICTURE_SET message so that the
     * native allocation can be freed.
     */
    private native int nativeDraw(Canvas canvas, RectF visibleRect,
            int color, int extra, boolean splitIfNeeded);
    private native void     nativeDumpDisplayTree(String urlOrNull);
    private native boolean  nativeEvaluateLayersAnimations(int nativeInstance);
    private native int      nativeGetDrawGLFunction(int nativeInstance, Rect rect,
            Rect viewRect, RectF visibleRect, float scale, int extras);
    private native void     nativeUpdateDrawGLFunction(Rect rect, Rect viewRect,
            RectF visibleRect, float scale);
    private native void     nativeExtendSelection(int x, int y);
    private native int      nativeFindAll(String findLower, String findUpper,
            boolean sameAsLastSearch);
    private native void     nativeFindNext(boolean forward);
    /* package */ native int      nativeFocusCandidateFramePointer();
    /* package */ native boolean  nativeFocusCandidateHasNextTextfield();
    /* package */ native boolean  nativeFocusCandidateIsPassword();
    private native boolean  nativeFocusCandidateIsRtlText();
    private native boolean  nativeFocusCandidateIsTextInput();
    private native boolean nativeFocusCandidateIsEditableText(int nativeClass);
    /* package */ native int      nativeFocusCandidateMaxLength();
    /* package */ native boolean  nativeFocusCandidateIsAutoComplete();
    /* package */ native boolean  nativeFocusCandidateIsSpellcheck();
    /* package */ native String   nativeFocusCandidateName();
    private native Rect     nativeFocusCandidateNodeBounds();
    /**
     * @return A Rect with left, top, right, bottom set to the corresponding
     * padding values in the focus candidate, if it is a textfield/textarea with
     * a style.  Otherwise return null.  This is not actually a rectangle; Rect
     * is being used to pass four integers.
     */
    private native Rect     nativeFocusCandidatePaddingRect();
    /* package */ native int      nativeFocusCandidatePointer();
    private native String   nativeFocusCandidateText();
    /* package */ native float    nativeFocusCandidateTextSize();
    /* package */ native int nativeFocusCandidateLineHeight();
    /**
     * Returns an integer corresponding to WebView.cpp::type.
     * See WebTextView.setType()
     */
    private native int      nativeFocusCandidateType();
    private native int      nativeFocusCandidateLayerId();
    private native boolean  nativeFocusIsPlugin();
    private native Rect     nativeFocusNodeBounds();
    /* package */ native int nativeFocusNodePointer();
    private native Rect     nativeGetCursorRingBounds();
    private native String   nativeGetSelection();
    private native boolean  nativeHasCursorNode();
    private native boolean  nativeHasFocusNode();
    private native void     nativeHideCursor();
    private native boolean  nativeHitSelection(int x, int y);
    private native String   nativeImageURI(int x, int y);
    private native Rect     nativeLayerBounds(int layer);
    /* package */ native boolean nativeMoveCursorToNextTextInput();
    // return true if the page has been scrolled
    private native boolean  nativeMotionUp(int x, int y, int slop);
    // returns false if it handled the key
    private native boolean  nativeMoveCursor(int keyCode, int count,
            boolean noScroll);
    private native int      nativeMoveGeneration();
    /**
     * @return true if the page should get the shift and arrow keys, rather
     * than select text/navigation.
     *
     * If the focus is a plugin, or if the focus and cursor match and are
     * a contentEditable element, then the page should handle these keys.
     */
    private native boolean  nativePageShouldHandleShiftAndArrows();
    private native boolean  nativePointInNavCache(int x, int y, int slop);
    private native void     nativeSelectBestAt(Rect rect);
    private native void     nativeSelectAt(int x, int y);
    private native int      nativeFindIndex();
    private native void     nativeSetExtendSelection();
    private native void     nativeSetFindIsEmpty();
    private native void     nativeSetFindIsUp(boolean isUp);
    private native void     nativeSetHeightCanMeasure(boolean measure);
    private native boolean  nativeSetBaseLayer(int nativeInstance,
            int layer, Region invalRegion,
            boolean showVisualIndicator, boolean isPictureAfterFirstLayout);
    private native int      nativeGetBaseLayer();
    private native void     nativeShowCursorTimed();
    private native void     nativeReplaceBaseContent(int content);
    private native void     nativeCopyBaseContentToPicture(Picture pict);
    private native boolean  nativeHasContent();
    private native void     nativeSetSelectionPointer(int nativeInstance,
            boolean set, float scale, int x, int y);
    private native boolean  nativeStartSelection(int x, int y);
    private native void     nativeStopGL();
    private native Rect     nativeSubtractLayers(Rect content);
    private native int      nativeTextGeneration();
    private native void     nativeDiscardAllTextures();
    private native void     nativeTileProfilingStart();
    private native float    nativeTileProfilingStop();
    private native void     nativeTileProfilingClear();
    private native int      nativeTileProfilingNumFrames();
    private native int      nativeTileProfilingNumTilesInFrame(int frame);
    private native int      nativeTileProfilingGetInt(int frame, int tile, String key);
    private native float    nativeTileProfilingGetFloat(int frame, int tile, String key);
    // Never call this version except by updateCachedTextfield(String) -
    // we always want to pass in our generation number.
    private native void     nativeUpdateCachedTextfield(String updatedText,
            int generation);
    private native boolean  nativeWordSelection(int x, int y);
    // return NO_LEFTEDGE means failure.
    static final int NO_LEFTEDGE = -1;
    native int nativeGetBlockLeftEdge(int x, int y, float scale);

    private native void     nativeUseHardwareAccelSkia(boolean enabled);

    // Returns a pointer to the scrollable LayerAndroid at the given point.
    private native int      nativeScrollableLayer(int x, int y, Rect scrollRect,
            Rect scrollBounds);
    /**
     * Scroll the specified layer.
     * @param layer Id of the layer to scroll, as determined by nativeScrollableLayer.
     * @param newX Destination x position to which to scroll.
     * @param newY Destination y position to which to scroll.
     * @return True if the layer is successfully scrolled.
     */
    private native boolean  nativeScrollLayer(int layer, int newX, int newY);
    private native void     nativeSetIsScrolling(boolean isScrolling);
    private native int      nativeGetBackgroundColor();
    native boolean  nativeSetProperty(String key, String value);
    native String   nativeGetProperty(String key);
    /**
     * See {@link ComponentCallbacks2} for the trim levels and descriptions
     */
    private static native void     nativeOnTrimMemory(int level);
    private static native void nativeSetPauseDrawing(int instance, boolean pause);
    private static native boolean nativeDisableNavcache();
    private static native void nativeSetTextSelection(int instance, int selection);
    private static native int nativeGetHandleLayerId(int instance, int handle,
            Rect cursorLocation);
    private static native boolean nativeIsBaseFirst(int instance);
}