accessibility_manager.h revision a1401311d1ab56c4ed0a474bd38c108f75cb0cd9 
1// Copyright (c) 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CHROME_BROWSER_CHROMEOS_ACCESSIBILITY_ACCESSIBILITY_MANAGER_H_
6#define CHROME_BROWSER_CHROMEOS_ACCESSIBILITY_ACCESSIBILITY_MANAGER_H_
7
8#include <set>
9
10#include "ash/accessibility_delegate.h"
11#include "ash/session_state_observer.h"
12#include "base/callback_list.h"
13#include "base/memory/weak_ptr.h"
14#include "base/prefs/pref_change_registrar.h"
15#include "base/time/time.h"
16#include "chrome/browser/chromeos/accessibility/accessibility_util.h"
17#include "chrome/browser/extensions/api/braille_display_private/braille_controller.h"
18#include "content/public/browser/notification_observer.h"
19#include "content/public/browser/notification_registrar.h"
20#include "extensions/browser/event_router.h"
21#include "extensions/browser/extension_system.h"
22
23namespace content {
24class RenderViewHost;
25}
26class Profile;
27
28namespace chromeos {
29
30enum AccessibilityNotificationType {
31  ACCESSIBILITY_MANAGER_SHUTDOWN,
32  ACCESSIBILITY_TOGGLE_HIGH_CONTRAST_MODE,
33  ACCESSIBILITY_TOGGLE_LARGE_CURSOR,
34  ACCESSIBILITY_TOGGLE_SCREEN_MAGNIFIER,
35  ACCESSIBILITY_TOGGLE_SPOKEN_FEEDBACK,
36  ACCESSIBILITY_TOGGLE_VIRTUAL_KEYBOARD
37};
38
39struct AccessibilityStatusEventDetails {
40  AccessibilityStatusEventDetails(
41      AccessibilityNotificationType notification_type,
42      bool enabled,
43      ash::AccessibilityNotificationVisibility notify);
44
45  AccessibilityStatusEventDetails(
46      AccessibilityNotificationType notification_type,
47      bool enabled,
48      ash::MagnifierType magnifier_type,
49      ash::AccessibilityNotificationVisibility notify);
50
51  AccessibilityNotificationType notification_type;
52  bool enabled;
53  ash::MagnifierType magnifier_type;
54  ash::AccessibilityNotificationVisibility notify;
55};
56
57typedef base::Callback<void(const AccessibilityStatusEventDetails&)>
58    AccessibilityStatusCallback;
59
60typedef base::CallbackList<void(const AccessibilityStatusEventDetails&)>
61    AccessibilityStatusCallbackList;
62
63typedef AccessibilityStatusCallbackList::Subscription
64    AccessibilityStatusSubscription;
65
66// AccessibilityManager changes the statuses of accessibility features
67// watching profile notifications and pref-changes.
68// TODO(yoshiki): merge MagnificationManager with AccessibilityManager.
69class AccessibilityManager : public content::NotificationObserver,
70    extensions::api::braille_display_private::BrailleObserver,
71    public ash::SessionStateObserver {
72 public:
73  // Creates an instance of AccessibilityManager, this should be called once,
74  // because only one instance should exist at the same time.
75  static void Initialize();
76  // Deletes the existing instance of AccessibilityManager.
77  static void Shutdown();
78  // Returns the existing instance. If there is no instance, returns NULL.
79  static AccessibilityManager* Get();
80
81  // On a user's first login into a device, any a11y features enabled/disabled
82  // by the user on the login screen are enabled/disabled in the user's profile.
83  // This class watches for profile changes and copies settings into the user's
84  // profile when it detects a login with a newly created profile.
85  class PrefHandler {
86   public:
87    explicit PrefHandler(const char* pref_path);
88    virtual ~PrefHandler();
89
90    // Should be called from AccessibilityManager::SetProfile().
91    void HandleProfileChanged(Profile* previous_profile,
92                              Profile* current_profile);
93
94   private:
95    const char* pref_path_;
96  };
97
98  // Returns true when the accessibility menu should be shown.
99  bool ShouldShowAccessibilityMenu();
100
101  // Returns true when cursor compositing should be enabled.
102  bool ShouldEnableCursorCompositing();
103
104  // Enables or disables the large cursor.
105  void EnableLargeCursor(bool enabled);
106  // Returns true if the large cursor is enabled, or false if not.
107  bool IsLargeCursorEnabled();
108
109  // Enables or disable Sticky Keys.
110  void EnableStickyKeys(bool enabled);
111
112  // Returns true if Incognito mode is allowed, or false if not.
113  bool IsIncognitoAllowed();
114
115  // Returns true if the Sticky Keys is enabled, or false if not.
116  bool IsStickyKeysEnabled();
117
118  // Enables or disables spoken feedback. Enabling spoken feedback installs the
119  // ChromeVox component extension.
120  void EnableSpokenFeedback(bool enabled,
121                            ash::AccessibilityNotificationVisibility notify);
122
123  // Returns true if spoken feedback is enabled, or false if not.
124  bool IsSpokenFeedbackEnabled();
125
126  // Toggles whether Chrome OS spoken feedback is on or off.
127  void ToggleSpokenFeedback(ash::AccessibilityNotificationVisibility notify);
128
129  // Enables or disables the high contrast mode for Chrome.
130  void EnableHighContrast(bool enabled);
131
132  // Returns true if High Contrast is enabled, or false if not.
133  bool IsHighContrastEnabled();
134
135  // Enables or disables autoclick.
136  void EnableAutoclick(bool enabled);
137
138  // Returns true if autoclick is enabled.
139  bool IsAutoclickEnabled();
140
141  // Set the delay for autoclicking after stopping the cursor in milliseconds.
142  void SetAutoclickDelay(int delay_ms);
143
144  // Returns the autoclick delay in milliseconds.
145  int GetAutoclickDelay() const;
146
147  // Enables or disables the virtual keyboard.
148  void EnableVirtualKeyboard(bool enabled);
149  // Returns true if the virtual keyboard is enabled, otherwise false.
150  bool IsVirtualKeyboardEnabled();
151
152  // SessionStateObserver overrides:
153  virtual void ActiveUserChanged(const std::string& user_id) OVERRIDE;
154
155  void SetProfileForTest(Profile* profile);
156
157  static void SetBrailleControllerForTest(
158      extensions::api::braille_display_private::BrailleController* controller);
159
160  // Enables/disables system sounds.
161  void EnableSystemSounds(bool system_sounds_enabled);
162
163  // Initiates play of shutdown sound and returns it's duration.
164  base::TimeDelta PlayShutdownSound();
165
166  // Injects ChromeVox scripts into given |render_view_host|.
167  void InjectChromeVox(content::RenderViewHost* render_view_host);
168
169  // Register a callback to be notified when the status of an accessibility
170  // option changes.
171  scoped_ptr<AccessibilityStatusSubscription> RegisterCallback(
172      const AccessibilityStatusCallback& cb);
173
174  // Notify registered callbacks of a status change in an accessibility setting.
175  void NotifyAccessibilityStatusChanged(
176      AccessibilityStatusEventDetails& details);
177
178  // Notify accessibility when locale changes occur.
179  void OnLocaleChanged();
180
181 protected:
182  AccessibilityManager();
183  virtual ~AccessibilityManager();
184
185 private:
186  void LoadChromeVox();
187  void LoadChromeVoxToUserScreen();
188  void LoadChromeVoxToLockScreen();
189  void UnloadChromeVox();
190  void UnloadChromeVoxFromLockScreen();
191  void PostLoadChromeVox(Profile* profile);
192  void PostUnloadChromeVox(Profile* profile);
193
194  void UpdateLargeCursorFromPref();
195  void UpdateStickyKeysFromPref();
196  void UpdateSpokenFeedbackFromPref();
197  void UpdateHighContrastFromPref();
198  void UpdateAutoclickFromPref();
199  void UpdateAutoclickDelayFromPref();
200  void UpdateVirtualKeyboardFromPref();
201
202  void CheckBrailleState();
203  void ReceiveBrailleDisplayState(
204      scoped_ptr<extensions::api::braille_display_private::DisplayState> state);
205
206  void SetProfile(Profile* profile);
207
208  void UpdateChromeOSAccessibilityHistograms();
209
210  // content::NotificationObserver implementation:
211  virtual void Observe(int type,
212                       const content::NotificationSource& source,
213                       const content::NotificationDetails& details) OVERRIDE;
214
215  // extensions::api::braille_display_private::BrailleObserver implementation.
216  // Enables spoken feedback if a braille display becomes available.
217  virtual void OnDisplayStateChanged(
218      const extensions::api::braille_display_private::DisplayState&
219          display_state) OVERRIDE;
220
221  // Profile which has the current a11y context.
222  Profile* profile_;
223
224  // Profile which ChromeVox is currently loaded to. If NULL, ChromeVox is not
225  // loaded to any profile.
226  bool chrome_vox_loaded_on_lock_screen_;
227  bool chrome_vox_loaded_on_user_screen_;
228
229  content::NotificationRegistrar notification_registrar_;
230  scoped_ptr<PrefChangeRegistrar> pref_change_registrar_;
231  scoped_ptr<PrefChangeRegistrar> local_state_pref_change_registrar_;
232  scoped_ptr<ash::ScopedSessionStateObserver> session_state_observer_;
233
234  PrefHandler large_cursor_pref_handler_;
235  PrefHandler spoken_feedback_pref_handler_;
236  PrefHandler high_contrast_pref_handler_;
237  PrefHandler autoclick_pref_handler_;
238  PrefHandler autoclick_delay_pref_handler_;
239  PrefHandler virtual_keyboard_pref_handler_;
240
241  bool large_cursor_enabled_;
242  bool sticky_keys_enabled_;
243  bool spoken_feedback_enabled_;
244  bool high_contrast_enabled_;
245  bool autoclick_enabled_;
246  int autoclick_delay_ms_;
247  bool virtual_keyboard_enabled_;
248
249  ash::AccessibilityNotificationVisibility spoken_feedback_notification_;
250
251  base::WeakPtrFactory<AccessibilityManager> weak_ptr_factory_;
252
253  bool should_speak_chrome_vox_announcements_on_user_screen_;
254
255  bool system_sounds_enabled_;
256
257  AccessibilityStatusCallbackList callback_list_;
258
259  DISALLOW_COPY_AND_ASSIGN(AccessibilityManager);
260};
261
262}  // namespace chromeos
263
264#endif  // CHROME_BROWSER_CHROMEOS_ACCESSIBILITY_ACCESSIBILITY_MANAGER_H_
265