1// Copyright 2011 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#include "cc/trees/layer_tree_impl.h"
6
7#include <limits>
8#include <set>
9
10#include "base/debug/trace_event.h"
11#include "base/debug/trace_event_argument.h"
12#include "cc/animation/keyframed_animation_curve.h"
13#include "cc/animation/scrollbar_animation_controller.h"
14#include "cc/animation/scrollbar_animation_controller_linear_fade.h"
15#include "cc/animation/scrollbar_animation_controller_thinning.h"
16#include "cc/base/math_util.h"
17#include "cc/base/util.h"
18#include "cc/debug/devtools_instrumentation.h"
19#include "cc/debug/traced_value.h"
20#include "cc/input/page_scale_animation.h"
21#include "cc/layers/heads_up_display_layer_impl.h"
22#include "cc/layers/layer.h"
23#include "cc/layers/layer_iterator.h"
24#include "cc/layers/render_surface_impl.h"
25#include "cc/layers/scrollbar_layer_impl_base.h"
26#include "cc/resources/ui_resource_request.h"
27#include "cc/trees/layer_tree_host_common.h"
28#include "cc/trees/layer_tree_host_impl.h"
29#include "cc/trees/occlusion_tracker.h"
30#include "ui/gfx/point_conversions.h"
31#include "ui/gfx/size_conversions.h"
32#include "ui/gfx/vector2d_conversions.h"
33
34namespace cc {
35
36// This class exists to split the LayerScrollOffsetDelegate between the
37// InnerViewportScrollLayer and the OuterViewportScrollLayer in a manner
38// that never requires the embedder or LayerImpl to know about.
39class LayerScrollOffsetDelegateProxy : public LayerImpl::ScrollOffsetDelegate {
40 public:
41  LayerScrollOffsetDelegateProxy(LayerImpl* layer,
42                                 LayerScrollOffsetDelegate* delegate,
43                                 LayerTreeImpl* layer_tree)
44      : layer_(layer), delegate_(delegate), layer_tree_impl_(layer_tree) {}
45  virtual ~LayerScrollOffsetDelegateProxy() {}
46
47  gfx::Vector2dF last_set_scroll_offset() const {
48    return last_set_scroll_offset_;
49  }
50
51  // LayerScrollOffsetDelegate implementation.
52  virtual void SetTotalScrollOffset(const gfx::Vector2dF& new_offset) OVERRIDE {
53    last_set_scroll_offset_ = new_offset;
54    layer_tree_impl_->UpdateScrollOffsetDelegate();
55  }
56
57  virtual gfx::Vector2dF GetTotalScrollOffset() OVERRIDE {
58    return layer_tree_impl_->GetDelegatedScrollOffset(layer_);
59  }
60
61  virtual bool IsExternalFlingActive() const OVERRIDE {
62    return delegate_->IsExternalFlingActive();
63  }
64
65 private:
66  LayerImpl* layer_;
67  LayerScrollOffsetDelegate* delegate_;
68  LayerTreeImpl* layer_tree_impl_;
69  gfx::Vector2dF last_set_scroll_offset_;
70};
71
72LayerTreeImpl::LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl)
73    : layer_tree_host_impl_(layer_tree_host_impl),
74      source_frame_number_(-1),
75      hud_layer_(0),
76      currently_scrolling_layer_(NULL),
77      root_layer_scroll_offset_delegate_(NULL),
78      background_color_(0),
79      has_transparent_background_(false),
80      page_scale_layer_(NULL),
81      inner_viewport_scroll_layer_(NULL),
82      outer_viewport_scroll_layer_(NULL),
83      page_scale_factor_(1),
84      page_scale_delta_(1),
85      sent_page_scale_delta_(1),
86      min_page_scale_factor_(0),
87      max_page_scale_factor_(0),
88      scrolling_layer_id_from_previous_tree_(0),
89      contents_textures_purged_(false),
90      requires_high_res_to_draw_(false),
91      viewport_size_invalid_(false),
92      needs_update_draw_properties_(true),
93      needs_full_tree_sync_(true),
94      next_activation_forces_redraw_(false),
95      has_ever_been_drawn_(false),
96      render_surface_layer_list_id_(0),
97      top_controls_layout_height_(0),
98      top_controls_content_offset_(0),
99      top_controls_delta_(0),
100      sent_top_controls_delta_(0) {
101}
102
103LayerTreeImpl::~LayerTreeImpl() {
104  BreakSwapPromises(SwapPromise::SWAP_FAILS);
105
106  // Need to explicitly clear the tree prior to destroying this so that
107  // the LayerTreeImpl pointer is still valid in the LayerImpl dtor.
108  DCHECK(!root_layer_);
109  DCHECK(layers_with_copy_output_request_.empty());
110}
111
112void LayerTreeImpl::Shutdown() { root_layer_.reset(); }
113
114void LayerTreeImpl::ReleaseResources() {
115  if (root_layer_)
116    ReleaseResourcesRecursive(root_layer_.get());
117}
118
119void LayerTreeImpl::SetRootLayer(scoped_ptr<LayerImpl> layer) {
120  if (inner_viewport_scroll_layer_)
121    inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
122  if (outer_viewport_scroll_layer_)
123    outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
124  inner_viewport_scroll_delegate_proxy_.reset();
125  outer_viewport_scroll_delegate_proxy_.reset();
126
127  root_layer_ = layer.Pass();
128  currently_scrolling_layer_ = NULL;
129  inner_viewport_scroll_layer_ = NULL;
130  outer_viewport_scroll_layer_ = NULL;
131  page_scale_layer_ = NULL;
132
133  layer_tree_host_impl_->OnCanDrawStateChangedForTree();
134}
135
136LayerImpl* LayerTreeImpl::InnerViewportScrollLayer() const {
137  return inner_viewport_scroll_layer_;
138}
139
140LayerImpl* LayerTreeImpl::OuterViewportScrollLayer() const {
141  return outer_viewport_scroll_layer_;
142}
143
144gfx::Vector2dF LayerTreeImpl::TotalScrollOffset() const {
145  gfx::Vector2dF offset;
146
147  if (inner_viewport_scroll_layer_)
148    offset += inner_viewport_scroll_layer_->TotalScrollOffset();
149
150  if (outer_viewport_scroll_layer_)
151    offset += outer_viewport_scroll_layer_->TotalScrollOffset();
152
153  return offset;
154}
155
156gfx::Vector2dF LayerTreeImpl::TotalMaxScrollOffset() const {
157  gfx::Vector2dF offset;
158
159  if (inner_viewport_scroll_layer_)
160    offset += inner_viewport_scroll_layer_->MaxScrollOffset();
161
162  if (outer_viewport_scroll_layer_)
163    offset += outer_viewport_scroll_layer_->MaxScrollOffset();
164
165  return offset;
166}
167gfx::Vector2dF LayerTreeImpl::TotalScrollDelta() const {
168  DCHECK(inner_viewport_scroll_layer_);
169  gfx::Vector2dF delta = inner_viewport_scroll_layer_->ScrollDelta();
170
171  if (outer_viewport_scroll_layer_)
172    delta += outer_viewport_scroll_layer_->ScrollDelta();
173
174  return delta;
175}
176
177scoped_ptr<LayerImpl> LayerTreeImpl::DetachLayerTree() {
178  // Clear all data structures that have direct references to the layer tree.
179  scrolling_layer_id_from_previous_tree_ =
180    currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0;
181  if (inner_viewport_scroll_layer_)
182    inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
183  if (outer_viewport_scroll_layer_)
184    outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
185  inner_viewport_scroll_delegate_proxy_.reset();
186  outer_viewport_scroll_delegate_proxy_.reset();
187  inner_viewport_scroll_layer_ = NULL;
188  outer_viewport_scroll_layer_ = NULL;
189  page_scale_layer_ = NULL;
190  currently_scrolling_layer_ = NULL;
191
192  render_surface_layer_list_.clear();
193  set_needs_update_draw_properties();
194  return root_layer_.Pass();
195}
196
197void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
198  // The request queue should have been processed and does not require a push.
199  DCHECK_EQ(ui_resource_request_queue_.size(), 0u);
200
201  if (next_activation_forces_redraw_) {
202    target_tree->ForceRedrawNextActivation();
203    next_activation_forces_redraw_ = false;
204  }
205
206  target_tree->PassSwapPromises(&swap_promise_list_);
207
208  target_tree->top_controls_layout_height_ = top_controls_layout_height_;
209  target_tree->top_controls_content_offset_ = top_controls_content_offset_;
210  target_tree->top_controls_delta_ =
211      target_tree->top_controls_delta_ -
212          target_tree->sent_top_controls_delta_;
213  target_tree->sent_top_controls_delta_ = 0.f;
214
215  target_tree->SetPageScaleValues(
216      page_scale_factor(), min_page_scale_factor(), max_page_scale_factor(),
217      target_tree->page_scale_delta() / target_tree->sent_page_scale_delta());
218  target_tree->set_sent_page_scale_delta(1);
219
220  target_tree->page_scale_animation_ = page_scale_animation_.Pass();
221
222  if (page_scale_layer_ && inner_viewport_scroll_layer_) {
223    target_tree->SetViewportLayersFromIds(
224        page_scale_layer_->id(),
225        inner_viewport_scroll_layer_->id(),
226        outer_viewport_scroll_layer_ ? outer_viewport_scroll_layer_->id()
227                                     : Layer::INVALID_ID);
228  } else {
229    target_tree->ClearViewportLayers();
230  }
231
232  target_tree->RegisterSelection(selection_start_, selection_end_);
233
234  // This should match the property synchronization in
235  // LayerTreeHost::finishCommitOnImplThread().
236  target_tree->set_source_frame_number(source_frame_number());
237  target_tree->set_background_color(background_color());
238  target_tree->set_has_transparent_background(has_transparent_background());
239
240  if (ContentsTexturesPurged())
241    target_tree->SetContentsTexturesPurged();
242  else
243    target_tree->ResetContentsTexturesPurged();
244
245  if (ViewportSizeInvalid())
246    target_tree->SetViewportSizeInvalid();
247  else
248    target_tree->ResetViewportSizeInvalid();
249
250  if (hud_layer())
251    target_tree->set_hud_layer(static_cast<HeadsUpDisplayLayerImpl*>(
252        LayerTreeHostCommon::FindLayerInSubtree(
253            target_tree->root_layer(), hud_layer()->id())));
254  else
255    target_tree->set_hud_layer(NULL);
256
257  target_tree->has_ever_been_drawn_ = false;
258}
259
260LayerImpl* LayerTreeImpl::InnerViewportContainerLayer() const {
261  return inner_viewport_scroll_layer_
262             ? inner_viewport_scroll_layer_->scroll_clip_layer()
263             : NULL;
264}
265
266LayerImpl* LayerTreeImpl::CurrentlyScrollingLayer() const {
267  DCHECK(IsActiveTree());
268  return currently_scrolling_layer_;
269}
270
271void LayerTreeImpl::SetCurrentlyScrollingLayer(LayerImpl* layer) {
272  if (currently_scrolling_layer_ == layer)
273    return;
274
275  if (currently_scrolling_layer_ &&
276      currently_scrolling_layer_->scrollbar_animation_controller())
277    currently_scrolling_layer_->scrollbar_animation_controller()
278        ->DidScrollEnd();
279  currently_scrolling_layer_ = layer;
280  if (layer && layer->scrollbar_animation_controller())
281    layer->scrollbar_animation_controller()->DidScrollBegin();
282}
283
284void LayerTreeImpl::ClearCurrentlyScrollingLayer() {
285  SetCurrentlyScrollingLayer(NULL);
286  scrolling_layer_id_from_previous_tree_ = 0;
287}
288
289namespace {
290
291void ForceScrollbarParameterUpdateAfterScaleChange(LayerImpl* current_layer) {
292  if (!current_layer)
293    return;
294
295  while (current_layer) {
296    current_layer->ScrollbarParametersDidChange();
297    current_layer = current_layer->parent();
298  }
299}
300
301}  // namespace
302
303void LayerTreeImpl::SetPageScaleFactorAndLimits(float page_scale_factor,
304    float min_page_scale_factor, float max_page_scale_factor) {
305  SetPageScaleValues(page_scale_factor, min_page_scale_factor,
306      max_page_scale_factor, page_scale_delta_);
307}
308
309void LayerTreeImpl::SetPageScaleDelta(float delta) {
310  SetPageScaleValues(page_scale_factor_, min_page_scale_factor_,
311      max_page_scale_factor_, delta);
312}
313
314void LayerTreeImpl::SetPageScaleValues(float page_scale_factor,
315      float min_page_scale_factor, float max_page_scale_factor,
316      float page_scale_delta) {
317  bool page_scale_changed =
318      min_page_scale_factor != min_page_scale_factor_ ||
319      max_page_scale_factor != max_page_scale_factor_ ||
320      page_scale_factor != page_scale_factor_;
321
322  min_page_scale_factor_ = min_page_scale_factor;
323  max_page_scale_factor_ = max_page_scale_factor;
324  page_scale_factor_ = page_scale_factor;
325
326  float total = page_scale_factor_ * page_scale_delta;
327  if (min_page_scale_factor_ && total < min_page_scale_factor_)
328    page_scale_delta = min_page_scale_factor_ / page_scale_factor_;
329  else if (max_page_scale_factor_ && total > max_page_scale_factor_)
330    page_scale_delta = max_page_scale_factor_ / page_scale_factor_;
331
332  if (page_scale_delta_ == page_scale_delta && !page_scale_changed)
333    return;
334
335  if (page_scale_delta_ != page_scale_delta) {
336    page_scale_delta_ = page_scale_delta;
337
338    if (IsActiveTree()) {
339      LayerTreeImpl* pending_tree = layer_tree_host_impl_->pending_tree();
340      if (pending_tree) {
341        DCHECK_EQ(1, pending_tree->sent_page_scale_delta());
342        pending_tree->SetPageScaleDelta(
343            page_scale_delta_ / sent_page_scale_delta_);
344      }
345    }
346
347    set_needs_update_draw_properties();
348  }
349
350  if (root_layer_scroll_offset_delegate_) {
351    root_layer_scroll_offset_delegate_->UpdateRootLayerState(
352        TotalScrollOffset(),
353        TotalMaxScrollOffset(),
354        ScrollableSize(),
355        total_page_scale_factor(),
356        min_page_scale_factor_,
357        max_page_scale_factor_);
358  }
359
360  ForceScrollbarParameterUpdateAfterScaleChange(page_scale_layer());
361}
362
363gfx::SizeF LayerTreeImpl::ScrollableViewportSize() const {
364  if (!InnerViewportContainerLayer())
365    return gfx::SizeF();
366
367  return gfx::ScaleSize(InnerViewportContainerLayer()->bounds(),
368                        1.0f / total_page_scale_factor());
369}
370
371gfx::Rect LayerTreeImpl::RootScrollLayerDeviceViewportBounds() const {
372  LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
373                                     ? OuterViewportScrollLayer()
374                                     : InnerViewportScrollLayer();
375  if (!root_scroll_layer || root_scroll_layer->children().empty())
376    return gfx::Rect();
377  LayerImpl* layer = root_scroll_layer->children()[0];
378  return MathUtil::MapEnclosingClippedRect(layer->screen_space_transform(),
379                                           gfx::Rect(layer->content_bounds()));
380}
381
382static void ApplySentScrollDeltasFromAbortedCommitTo(LayerImpl* layer) {
383  layer->ApplySentScrollDeltasFromAbortedCommit();
384}
385
386void LayerTreeImpl::ApplySentScrollAndScaleDeltasFromAbortedCommit() {
387  DCHECK(IsActiveTree());
388
389  page_scale_factor_ *= sent_page_scale_delta_;
390  page_scale_delta_ /= sent_page_scale_delta_;
391  sent_page_scale_delta_ = 1.f;
392
393  top_controls_content_offset_ += sent_top_controls_delta_;
394  top_controls_delta_ -= sent_top_controls_delta_;
395  sent_top_controls_delta_ = 0.f;
396
397  if (!root_layer())
398    return;
399
400  LayerTreeHostCommon::CallFunctionForSubtree(
401      root_layer(), base::Bind(&ApplySentScrollDeltasFromAbortedCommitTo));
402}
403
404static void ApplyScrollDeltasSinceBeginMainFrameTo(LayerImpl* layer) {
405  layer->ApplyScrollDeltasSinceBeginMainFrame();
406}
407
408void LayerTreeImpl::ApplyScrollDeltasSinceBeginMainFrame() {
409  DCHECK(IsPendingTree());
410  if (!root_layer())
411    return;
412
413  LayerTreeHostCommon::CallFunctionForSubtree(
414      root_layer(), base::Bind(&ApplyScrollDeltasSinceBeginMainFrameTo));
415}
416
417void LayerTreeImpl::SetViewportLayersFromIds(
418    int page_scale_layer_id,
419    int inner_viewport_scroll_layer_id,
420    int outer_viewport_scroll_layer_id) {
421  page_scale_layer_ = LayerById(page_scale_layer_id);
422  DCHECK(page_scale_layer_);
423
424  inner_viewport_scroll_layer_ =
425      LayerById(inner_viewport_scroll_layer_id);
426  DCHECK(inner_viewport_scroll_layer_);
427
428  outer_viewport_scroll_layer_ =
429      LayerById(outer_viewport_scroll_layer_id);
430  DCHECK(outer_viewport_scroll_layer_ ||
431         outer_viewport_scroll_layer_id == Layer::INVALID_ID);
432
433  if (!root_layer_scroll_offset_delegate_)
434    return;
435
436  inner_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
437      new LayerScrollOffsetDelegateProxy(inner_viewport_scroll_layer_,
438                                         root_layer_scroll_offset_delegate_,
439                                         this));
440
441  if (outer_viewport_scroll_layer_)
442    outer_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
443        new LayerScrollOffsetDelegateProxy(outer_viewport_scroll_layer_,
444                                           root_layer_scroll_offset_delegate_,
445                                           this));
446}
447
448void LayerTreeImpl::ClearViewportLayers() {
449  page_scale_layer_ = NULL;
450  inner_viewport_scroll_layer_ = NULL;
451  outer_viewport_scroll_layer_ = NULL;
452}
453
454bool LayerTreeImpl::UpdateDrawProperties() {
455  if (!needs_update_draw_properties_)
456    return true;
457
458  // For max_texture_size.
459  if (!layer_tree_host_impl_->renderer())
460    return false;
461
462  if (!root_layer())
463    return false;
464
465  needs_update_draw_properties_ = false;
466  render_surface_layer_list_.clear();
467
468  {
469    TRACE_EVENT2("cc",
470                 "LayerTreeImpl::UpdateDrawProperties",
471                 "IsActive",
472                 IsActiveTree(),
473                 "SourceFrameNumber",
474                 source_frame_number_);
475    LayerImpl* page_scale_layer =
476        page_scale_layer_ ? page_scale_layer_ : InnerViewportContainerLayer();
477    bool can_render_to_separate_surface =
478        (layer_tree_host_impl_->GetDrawMode() !=
479         DRAW_MODE_RESOURCELESS_SOFTWARE);
480
481    ++render_surface_layer_list_id_;
482    LayerTreeHostCommon::CalcDrawPropsImplInputs inputs(
483        root_layer(),
484        DrawViewportSize(),
485        layer_tree_host_impl_->DrawTransform(),
486        device_scale_factor(),
487        total_page_scale_factor(),
488        page_scale_layer,
489        resource_provider()->max_texture_size(),
490        settings().can_use_lcd_text,
491        can_render_to_separate_surface,
492        settings().layer_transforms_should_scale_layer_contents,
493        &render_surface_layer_list_,
494        render_surface_layer_list_id_);
495    LayerTreeHostCommon::CalculateDrawProperties(&inputs);
496  }
497
498  {
499    TRACE_EVENT2("cc",
500                 "LayerTreeImpl::UpdateTilePriorities",
501                 "IsActive",
502                 IsActiveTree(),
503                 "SourceFrameNumber",
504                 source_frame_number_);
505    scoped_ptr<OcclusionTracker<LayerImpl> > occlusion_tracker;
506    if (settings().use_occlusion_for_tile_prioritization) {
507      occlusion_tracker.reset(new OcclusionTracker<LayerImpl>(
508          root_layer()->render_surface()->content_rect()));
509      occlusion_tracker->set_minimum_tracking_size(
510          settings().minimum_occlusion_tracking_size);
511    }
512
513    bool resourceless_software_draw = (layer_tree_host_impl_->GetDrawMode() ==
514                                       DRAW_MODE_RESOURCELESS_SOFTWARE);
515
516    // LayerIterator is used here instead of CallFunctionForSubtree to only
517    // UpdateTilePriorities on layers that will be visible (and thus have valid
518    // draw properties) and not because any ordering is required.
519    typedef LayerIterator<LayerImpl> LayerIteratorType;
520    LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
521    for (LayerIteratorType it =
522             LayerIteratorType::Begin(&render_surface_layer_list_);
523         it != end;
524         ++it) {
525      if (occlusion_tracker)
526        occlusion_tracker->EnterLayer(it);
527
528      LayerImpl* layer = *it;
529      const Occlusion& occlusion_in_content_space =
530          occlusion_tracker ? occlusion_tracker->GetCurrentOcclusionForLayer(
531                                  layer->draw_transform())
532                            : Occlusion();
533
534      if (it.represents_itself()) {
535        layer->UpdateTiles(occlusion_in_content_space,
536                           resourceless_software_draw);
537      }
538
539      if (!it.represents_contributing_render_surface()) {
540        if (occlusion_tracker)
541          occlusion_tracker->LeaveLayer(it);
542        continue;
543      }
544
545      if (layer->mask_layer()) {
546        layer->mask_layer()->UpdateTiles(occlusion_in_content_space,
547                                         resourceless_software_draw);
548      }
549      if (layer->replica_layer() && layer->replica_layer()->mask_layer()) {
550        layer->replica_layer()->mask_layer()->UpdateTiles(
551            occlusion_in_content_space, resourceless_software_draw);
552      }
553
554      if (occlusion_tracker)
555        occlusion_tracker->LeaveLayer(it);
556    }
557  }
558
559  DCHECK(!needs_update_draw_properties_) <<
560      "CalcDrawProperties should not set_needs_update_draw_properties()";
561  return true;
562}
563
564const LayerImplList& LayerTreeImpl::RenderSurfaceLayerList() const {
565  // If this assert triggers, then the list is dirty.
566  DCHECK(!needs_update_draw_properties_);
567  return render_surface_layer_list_;
568}
569
570gfx::Size LayerTreeImpl::ScrollableSize() const {
571  LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
572                                     ? OuterViewportScrollLayer()
573                                     : InnerViewportScrollLayer();
574  if (!root_scroll_layer || root_scroll_layer->children().empty())
575    return gfx::Size();
576  return root_scroll_layer->children()[0]->bounds();
577}
578
579LayerImpl* LayerTreeImpl::LayerById(int id) {
580  LayerIdMap::iterator iter = layer_id_map_.find(id);
581  return iter != layer_id_map_.end() ? iter->second : NULL;
582}
583
584void LayerTreeImpl::RegisterLayer(LayerImpl* layer) {
585  DCHECK(!LayerById(layer->id()));
586  layer_id_map_[layer->id()] = layer;
587}
588
589void LayerTreeImpl::UnregisterLayer(LayerImpl* layer) {
590  DCHECK(LayerById(layer->id()));
591  layer_id_map_.erase(layer->id());
592}
593
594size_t LayerTreeImpl::NumLayers() {
595  return layer_id_map_.size();
596}
597
598void LayerTreeImpl::PushPersistedState(LayerTreeImpl* pending_tree) {
599  pending_tree->SetCurrentlyScrollingLayer(
600      LayerTreeHostCommon::FindLayerInSubtree(pending_tree->root_layer(),
601          currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0));
602}
603
604static void DidBecomeActiveRecursive(LayerImpl* layer) {
605  layer->DidBecomeActive();
606  if (layer->mask_layer())
607    layer->mask_layer()->DidBecomeActive();
608  if (layer->replica_layer() && layer->replica_layer()->mask_layer())
609    layer->replica_layer()->mask_layer()->DidBecomeActive();
610
611  for (size_t i = 0; i < layer->children().size(); ++i)
612    DidBecomeActiveRecursive(layer->children()[i]);
613}
614
615void LayerTreeImpl::DidBecomeActive() {
616  if (next_activation_forces_redraw_) {
617    layer_tree_host_impl_->SetFullRootLayerDamage();
618    next_activation_forces_redraw_ = false;
619  }
620
621  if (scrolling_layer_id_from_previous_tree_) {
622    currently_scrolling_layer_ = LayerTreeHostCommon::FindLayerInSubtree(
623        root_layer(), scrolling_layer_id_from_previous_tree_);
624  }
625
626  // Always reset this flag on activation, as we would only have activated
627  // if we were in a good state.
628  ResetRequiresHighResToDraw();
629
630  if (root_layer())
631    DidBecomeActiveRecursive(root_layer());
632
633  devtools_instrumentation::DidActivateLayerTree(layer_tree_host_impl_->id(),
634                                                 source_frame_number_);
635}
636
637bool LayerTreeImpl::ContentsTexturesPurged() const {
638  return contents_textures_purged_;
639}
640
641void LayerTreeImpl::SetContentsTexturesPurged() {
642  if (contents_textures_purged_)
643    return;
644  contents_textures_purged_ = true;
645  layer_tree_host_impl_->OnCanDrawStateChangedForTree();
646}
647
648void LayerTreeImpl::ResetContentsTexturesPurged() {
649  if (!contents_textures_purged_)
650    return;
651  contents_textures_purged_ = false;
652  layer_tree_host_impl_->OnCanDrawStateChangedForTree();
653}
654
655void LayerTreeImpl::SetRequiresHighResToDraw() {
656  requires_high_res_to_draw_ = true;
657}
658
659void LayerTreeImpl::ResetRequiresHighResToDraw() {
660  requires_high_res_to_draw_ = false;
661}
662
663bool LayerTreeImpl::RequiresHighResToDraw() const {
664  return requires_high_res_to_draw_;
665}
666
667bool LayerTreeImpl::ViewportSizeInvalid() const {
668  return viewport_size_invalid_;
669}
670
671void LayerTreeImpl::SetViewportSizeInvalid() {
672  viewport_size_invalid_ = true;
673  layer_tree_host_impl_->OnCanDrawStateChangedForTree();
674}
675
676void LayerTreeImpl::ResetViewportSizeInvalid() {
677  viewport_size_invalid_ = false;
678  layer_tree_host_impl_->OnCanDrawStateChangedForTree();
679}
680
681Proxy* LayerTreeImpl::proxy() const {
682  return layer_tree_host_impl_->proxy();
683}
684
685const LayerTreeSettings& LayerTreeImpl::settings() const {
686  return layer_tree_host_impl_->settings();
687}
688
689const RendererCapabilitiesImpl& LayerTreeImpl::GetRendererCapabilities() const {
690  return layer_tree_host_impl_->GetRendererCapabilities();
691}
692
693ContextProvider* LayerTreeImpl::context_provider() const {
694  return output_surface()->context_provider();
695}
696
697OutputSurface* LayerTreeImpl::output_surface() const {
698  return layer_tree_host_impl_->output_surface();
699}
700
701ResourceProvider* LayerTreeImpl::resource_provider() const {
702  return layer_tree_host_impl_->resource_provider();
703}
704
705TileManager* LayerTreeImpl::tile_manager() const {
706  return layer_tree_host_impl_->tile_manager();
707}
708
709FrameRateCounter* LayerTreeImpl::frame_rate_counter() const {
710  return layer_tree_host_impl_->fps_counter();
711}
712
713PaintTimeCounter* LayerTreeImpl::paint_time_counter() const {
714  return layer_tree_host_impl_->paint_time_counter();
715}
716
717MemoryHistory* LayerTreeImpl::memory_history() const {
718  return layer_tree_host_impl_->memory_history();
719}
720
721gfx::Size LayerTreeImpl::device_viewport_size() const {
722  return layer_tree_host_impl_->device_viewport_size();
723}
724
725bool LayerTreeImpl::IsActiveTree() const {
726  return layer_tree_host_impl_->active_tree() == this;
727}
728
729bool LayerTreeImpl::IsPendingTree() const {
730  return layer_tree_host_impl_->pending_tree() == this;
731}
732
733bool LayerTreeImpl::IsRecycleTree() const {
734  return layer_tree_host_impl_->recycle_tree() == this;
735}
736
737LayerImpl* LayerTreeImpl::FindActiveTreeLayerById(int id) {
738  LayerTreeImpl* tree = layer_tree_host_impl_->active_tree();
739  if (!tree)
740    return NULL;
741  return tree->LayerById(id);
742}
743
744LayerImpl* LayerTreeImpl::FindPendingTreeLayerById(int id) {
745  LayerTreeImpl* tree = layer_tree_host_impl_->pending_tree();
746  if (!tree)
747    return NULL;
748  return tree->LayerById(id);
749}
750
751LayerImpl* LayerTreeImpl::FindRecycleTreeLayerById(int id) {
752  LayerTreeImpl* tree = layer_tree_host_impl_->recycle_tree();
753  if (!tree)
754    return NULL;
755  return tree->LayerById(id);
756}
757
758bool LayerTreeImpl::PinchGestureActive() const {
759  return layer_tree_host_impl_->pinch_gesture_active();
760}
761
762BeginFrameArgs LayerTreeImpl::CurrentBeginFrameArgs() const {
763  return layer_tree_host_impl_->CurrentBeginFrameArgs();
764}
765
766base::TimeDelta LayerTreeImpl::begin_impl_frame_interval() const {
767  return layer_tree_host_impl_->begin_impl_frame_interval();
768}
769
770void LayerTreeImpl::SetNeedsCommit() {
771  layer_tree_host_impl_->SetNeedsCommit();
772}
773
774gfx::Rect LayerTreeImpl::DeviceViewport() const {
775  return layer_tree_host_impl_->DeviceViewport();
776}
777
778gfx::Size LayerTreeImpl::DrawViewportSize() const {
779  return layer_tree_host_impl_->DrawViewportSize();
780}
781
782const gfx::Rect LayerTreeImpl::ViewportRectForTilePriority() const {
783  return layer_tree_host_impl_->ViewportRectForTilePriority();
784}
785
786scoped_ptr<ScrollbarAnimationController>
787LayerTreeImpl::CreateScrollbarAnimationController(LayerImpl* scrolling_layer) {
788  DCHECK(settings().scrollbar_fade_delay_ms);
789  DCHECK(settings().scrollbar_fade_duration_ms);
790  base::TimeDelta delay =
791      base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_delay_ms);
792  base::TimeDelta duration =
793      base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_duration_ms);
794  switch (settings().scrollbar_animator) {
795    case LayerTreeSettings::LinearFade: {
796      return ScrollbarAnimationControllerLinearFade::Create(
797                 scrolling_layer, layer_tree_host_impl_, delay, duration)
798          .PassAs<ScrollbarAnimationController>();
799    }
800    case LayerTreeSettings::Thinning: {
801      return ScrollbarAnimationControllerThinning::Create(
802                 scrolling_layer, layer_tree_host_impl_, delay, duration)
803          .PassAs<ScrollbarAnimationController>();
804    }
805    case LayerTreeSettings::NoAnimator:
806      NOTREACHED();
807      break;
808  }
809  return scoped_ptr<ScrollbarAnimationController>();
810}
811
812void LayerTreeImpl::DidAnimateScrollOffset() {
813  layer_tree_host_impl_->DidAnimateScrollOffset();
814}
815
816bool LayerTreeImpl::use_gpu_rasterization() const {
817  return layer_tree_host_impl_->use_gpu_rasterization();
818}
819
820bool LayerTreeImpl::create_low_res_tiling() const {
821  return layer_tree_host_impl_->create_low_res_tiling();
822}
823
824void LayerTreeImpl::SetNeedsRedraw() {
825  layer_tree_host_impl_->SetNeedsRedraw();
826}
827
828const LayerTreeDebugState& LayerTreeImpl::debug_state() const {
829  return layer_tree_host_impl_->debug_state();
830}
831
832float LayerTreeImpl::device_scale_factor() const {
833  return layer_tree_host_impl_->device_scale_factor();
834}
835
836DebugRectHistory* LayerTreeImpl::debug_rect_history() const {
837  return layer_tree_host_impl_->debug_rect_history();
838}
839
840AnimationRegistrar* LayerTreeImpl::animationRegistrar() const {
841  return layer_tree_host_impl_->animation_registrar();
842}
843
844void LayerTreeImpl::GetAllTilesForTracing(std::set<const Tile*>* tiles) const {
845  typedef LayerIterator<LayerImpl> LayerIteratorType;
846  LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
847  for (LayerIteratorType it =
848           LayerIteratorType::Begin(&render_surface_layer_list_);
849       it != end;
850       ++it) {
851    if (!it.represents_itself())
852      continue;
853    LayerImpl* layer_impl = *it;
854    layer_impl->GetAllTilesForTracing(tiles);
855  }
856}
857
858void LayerTreeImpl::AsValueInto(base::debug::TracedValue* state) const {
859  TracedValue::MakeDictIntoImplicitSnapshot(state, "cc::LayerTreeImpl", this);
860  state->SetInteger("source_frame_number", source_frame_number_);
861
862  state->BeginDictionary("root_layer");
863  root_layer_->AsValueInto(state);
864  state->EndDictionary();
865
866  state->BeginArray("render_surface_layer_list");
867  typedef LayerIterator<LayerImpl> LayerIteratorType;
868  LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
869  for (LayerIteratorType it = LayerIteratorType::Begin(
870           &render_surface_layer_list_); it != end; ++it) {
871    if (!it.represents_itself())
872      continue;
873    TracedValue::AppendIDRef(*it, state);
874  }
875  state->EndArray();
876
877  state->BeginArray("swap_promise_trace_ids");
878  for (size_t i = 0; i < swap_promise_list_.size(); i++)
879    state->AppendDouble(swap_promise_list_[i]->TraceId());
880  state->EndArray();
881}
882
883void LayerTreeImpl::SetRootLayerScrollOffsetDelegate(
884    LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate) {
885  if (root_layer_scroll_offset_delegate_ == root_layer_scroll_offset_delegate)
886    return;
887
888  if (!root_layer_scroll_offset_delegate) {
889    // Make sure we remove the proxies from their layers before
890    // releasing them.
891    if (InnerViewportScrollLayer())
892      InnerViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
893    if (OuterViewportScrollLayer())
894      OuterViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
895    inner_viewport_scroll_delegate_proxy_.reset();
896    outer_viewport_scroll_delegate_proxy_.reset();
897  }
898
899  root_layer_scroll_offset_delegate_ = root_layer_scroll_offset_delegate;
900
901  if (root_layer_scroll_offset_delegate_) {
902    root_layer_scroll_offset_delegate_->UpdateRootLayerState(
903        TotalScrollOffset(),
904        TotalMaxScrollOffset(),
905        ScrollableSize(),
906        total_page_scale_factor(),
907        min_page_scale_factor(),
908        max_page_scale_factor());
909
910    if (inner_viewport_scroll_layer_) {
911      inner_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
912          new LayerScrollOffsetDelegateProxy(InnerViewportScrollLayer(),
913                                             root_layer_scroll_offset_delegate_,
914                                             this));
915      inner_viewport_scroll_layer_->SetScrollOffsetDelegate(
916          inner_viewport_scroll_delegate_proxy_.get());
917    }
918
919    if (outer_viewport_scroll_layer_) {
920      outer_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
921          new LayerScrollOffsetDelegateProxy(OuterViewportScrollLayer(),
922                                             root_layer_scroll_offset_delegate_,
923                                             this));
924      outer_viewport_scroll_layer_->SetScrollOffsetDelegate(
925          outer_viewport_scroll_delegate_proxy_.get());
926    }
927  }
928}
929
930void LayerTreeImpl::UpdateScrollOffsetDelegate() {
931  DCHECK(InnerViewportScrollLayer());
932  DCHECK(root_layer_scroll_offset_delegate_);
933
934  gfx::Vector2dF offset =
935      inner_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
936
937  if (OuterViewportScrollLayer())
938    offset += outer_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
939
940  root_layer_scroll_offset_delegate_->UpdateRootLayerState(
941      offset,
942      TotalMaxScrollOffset(),
943      ScrollableSize(),
944      total_page_scale_factor(),
945      min_page_scale_factor(),
946      max_page_scale_factor());
947}
948
949gfx::Vector2dF LayerTreeImpl::GetDelegatedScrollOffset(LayerImpl* layer) {
950  DCHECK(root_layer_scroll_offset_delegate_);
951  DCHECK(InnerViewportScrollLayer());
952  if (layer == InnerViewportScrollLayer() && !OuterViewportScrollLayer())
953    return root_layer_scroll_offset_delegate_->GetTotalScrollOffset();
954
955  // If we get here, we have both inner/outer viewports, and need to distribute
956  // the scroll offset between them.
957  DCHECK(inner_viewport_scroll_delegate_proxy_);
958  DCHECK(outer_viewport_scroll_delegate_proxy_);
959  gfx::Vector2dF inner_viewport_offset =
960      inner_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
961  gfx::Vector2dF outer_viewport_offset =
962      outer_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
963
964  // It may be nothing has changed.
965  gfx::Vector2dF delegate_offset =
966      root_layer_scroll_offset_delegate_->GetTotalScrollOffset();
967  if (inner_viewport_offset + outer_viewport_offset == delegate_offset) {
968    if (layer == InnerViewportScrollLayer())
969      return inner_viewport_offset;
970    else
971      return outer_viewport_offset;
972  }
973
974  gfx::Vector2d max_outer_viewport_scroll_offset =
975      OuterViewportScrollLayer()->MaxScrollOffset();
976
977  outer_viewport_offset = delegate_offset - inner_viewport_offset;
978  outer_viewport_offset.SetToMin(max_outer_viewport_scroll_offset);
979  outer_viewport_offset.SetToMax(gfx::Vector2d());
980
981  if (layer == OuterViewportScrollLayer())
982    return outer_viewport_offset;
983
984  inner_viewport_offset = delegate_offset - outer_viewport_offset;
985
986  return inner_viewport_offset;
987}
988
989void LayerTreeImpl::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {
990  DCHECK(swap_promise);
991  swap_promise_list_.push_back(swap_promise.Pass());
992}
993
994void LayerTreeImpl::PassSwapPromises(
995    ScopedPtrVector<SwapPromise>* new_swap_promise) {
996  swap_promise_list_.insert_and_take(swap_promise_list_.end(),
997                                     new_swap_promise);
998  new_swap_promise->clear();
999}
1000
1001void LayerTreeImpl::FinishSwapPromises(CompositorFrameMetadata* metadata) {
1002  for (size_t i = 0; i < swap_promise_list_.size(); i++)
1003    swap_promise_list_[i]->DidSwap(metadata);
1004  swap_promise_list_.clear();
1005}
1006
1007void LayerTreeImpl::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
1008  for (size_t i = 0; i < swap_promise_list_.size(); i++)
1009    swap_promise_list_[i]->DidNotSwap(reason);
1010  swap_promise_list_.clear();
1011}
1012
1013void LayerTreeImpl::DidModifyTilePriorities() {
1014  layer_tree_host_impl_->DidModifyTilePriorities();
1015}
1016
1017void LayerTreeImpl::set_ui_resource_request_queue(
1018    const UIResourceRequestQueue& queue) {
1019  ui_resource_request_queue_ = queue;
1020}
1021
1022ResourceProvider::ResourceId LayerTreeImpl::ResourceIdForUIResource(
1023    UIResourceId uid) const {
1024  return layer_tree_host_impl_->ResourceIdForUIResource(uid);
1025}
1026
1027bool LayerTreeImpl::IsUIResourceOpaque(UIResourceId uid) const {
1028  return layer_tree_host_impl_->IsUIResourceOpaque(uid);
1029}
1030
1031void LayerTreeImpl::ProcessUIResourceRequestQueue() {
1032  while (ui_resource_request_queue_.size() > 0) {
1033    UIResourceRequest req = ui_resource_request_queue_.front();
1034    ui_resource_request_queue_.pop_front();
1035
1036    switch (req.GetType()) {
1037      case UIResourceRequest::UIResourceCreate:
1038        layer_tree_host_impl_->CreateUIResource(req.GetId(), req.GetBitmap());
1039        break;
1040      case UIResourceRequest::UIResourceDelete:
1041        layer_tree_host_impl_->DeleteUIResource(req.GetId());
1042        break;
1043      case UIResourceRequest::UIResourceInvalidRequest:
1044        NOTREACHED();
1045        break;
1046    }
1047  }
1048
1049  // If all UI resource evictions were not recreated by processing this queue,
1050  // then another commit is required.
1051  if (layer_tree_host_impl_->EvictedUIResourcesExist())
1052    layer_tree_host_impl_->SetNeedsCommit();
1053}
1054
1055void LayerTreeImpl::AddLayerWithCopyOutputRequest(LayerImpl* layer) {
1056  // Only the active tree needs to know about layers with copy requests, as
1057  // they are aborted if not serviced during draw.
1058  DCHECK(IsActiveTree());
1059
1060  // DCHECK(std::find(layers_with_copy_output_request_.begin(),
1061  //                 layers_with_copy_output_request_.end(),
1062  //                 layer) == layers_with_copy_output_request_.end());
1063  // TODO(danakj): Remove this once crash is found crbug.com/309777
1064  for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1065    CHECK(layers_with_copy_output_request_[i] != layer)
1066        << i << " of " << layers_with_copy_output_request_.size();
1067  }
1068  layers_with_copy_output_request_.push_back(layer);
1069}
1070
1071void LayerTreeImpl::RemoveLayerWithCopyOutputRequest(LayerImpl* layer) {
1072  // Only the active tree needs to know about layers with copy requests, as
1073  // they are aborted if not serviced during draw.
1074  DCHECK(IsActiveTree());
1075
1076  std::vector<LayerImpl*>::iterator it = std::find(
1077      layers_with_copy_output_request_.begin(),
1078      layers_with_copy_output_request_.end(),
1079      layer);
1080  DCHECK(it != layers_with_copy_output_request_.end());
1081  layers_with_copy_output_request_.erase(it);
1082
1083  // TODO(danakj): Remove this once crash is found crbug.com/309777
1084  for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1085    CHECK(layers_with_copy_output_request_[i] != layer)
1086        << i << " of " << layers_with_copy_output_request_.size();
1087  }
1088}
1089
1090const std::vector<LayerImpl*>& LayerTreeImpl::LayersWithCopyOutputRequest()
1091    const {
1092  // Only the active tree needs to know about layers with copy requests, as
1093  // they are aborted if not serviced during draw.
1094  DCHECK(IsActiveTree());
1095
1096  return layers_with_copy_output_request_;
1097}
1098
1099void LayerTreeImpl::ReleaseResourcesRecursive(LayerImpl* current) {
1100  DCHECK(current);
1101  current->ReleaseResources();
1102  if (current->mask_layer())
1103    ReleaseResourcesRecursive(current->mask_layer());
1104  if (current->replica_layer())
1105    ReleaseResourcesRecursive(current->replica_layer());
1106  for (size_t i = 0; i < current->children().size(); ++i)
1107    ReleaseResourcesRecursive(current->children()[i]);
1108}
1109
1110template <typename LayerType>
1111static inline bool LayerClipsSubtree(LayerType* layer) {
1112  return layer->masks_to_bounds() || layer->mask_layer();
1113}
1114
1115static bool PointHitsRect(
1116    const gfx::PointF& screen_space_point,
1117    const gfx::Transform& local_space_to_screen_space_transform,
1118    const gfx::RectF& local_space_rect,
1119    float* distance_to_camera) {
1120  // If the transform is not invertible, then assume that this point doesn't hit
1121  // this rect.
1122  gfx::Transform inverse_local_space_to_screen_space(
1123      gfx::Transform::kSkipInitialization);
1124  if (!local_space_to_screen_space_transform.GetInverse(
1125          &inverse_local_space_to_screen_space))
1126    return false;
1127
1128  // Transform the hit test point from screen space to the local space of the
1129  // given rect.
1130  bool clipped = false;
1131  gfx::Point3F planar_point = MathUtil::ProjectPoint3D(
1132      inverse_local_space_to_screen_space, screen_space_point, &clipped);
1133  gfx::PointF hit_test_point_in_local_space =
1134      gfx::PointF(planar_point.x(), planar_point.y());
1135
1136  // If ProjectPoint could not project to a valid value, then we assume that
1137  // this point doesn't hit this rect.
1138  if (clipped)
1139    return false;
1140
1141  if (!local_space_rect.Contains(hit_test_point_in_local_space))
1142    return false;
1143
1144  if (distance_to_camera) {
1145    // To compute the distance to the camera, we have to take the planar point
1146    // and pull it back to world space and compute the displacement along the
1147    // z-axis.
1148    gfx::Point3F planar_point_in_screen_space(planar_point);
1149    local_space_to_screen_space_transform.TransformPoint(
1150        &planar_point_in_screen_space);
1151    *distance_to_camera = planar_point_in_screen_space.z();
1152  }
1153
1154  return true;
1155}
1156
1157static bool PointHitsRegion(const gfx::PointF& screen_space_point,
1158                            const gfx::Transform& screen_space_transform,
1159                            const Region& layer_space_region,
1160                            float layer_content_scale_x,
1161                            float layer_content_scale_y) {
1162  // If the transform is not invertible, then assume that this point doesn't hit
1163  // this region.
1164  gfx::Transform inverse_screen_space_transform(
1165      gfx::Transform::kSkipInitialization);
1166  if (!screen_space_transform.GetInverse(&inverse_screen_space_transform))
1167    return false;
1168
1169  // Transform the hit test point from screen space to the local space of the
1170  // given region.
1171  bool clipped = false;
1172  gfx::PointF hit_test_point_in_content_space = MathUtil::ProjectPoint(
1173      inverse_screen_space_transform, screen_space_point, &clipped);
1174  gfx::PointF hit_test_point_in_layer_space =
1175      gfx::ScalePoint(hit_test_point_in_content_space,
1176                      1.f / layer_content_scale_x,
1177                      1.f / layer_content_scale_y);
1178
1179  // If ProjectPoint could not project to a valid value, then we assume that
1180  // this point doesn't hit this region.
1181  if (clipped)
1182    return false;
1183
1184  return layer_space_region.Contains(
1185      gfx::ToRoundedPoint(hit_test_point_in_layer_space));
1186}
1187
1188static const LayerImpl* GetNextClippingLayer(const LayerImpl* layer) {
1189  if (layer->scroll_parent())
1190    return layer->scroll_parent();
1191  if (layer->clip_parent())
1192    return layer->clip_parent();
1193  return layer->parent();
1194}
1195
1196static bool PointIsClippedBySurfaceOrClipRect(
1197    const gfx::PointF& screen_space_point,
1198    const LayerImpl* layer) {
1199  // Walk up the layer tree and hit-test any render_surfaces and any layer
1200  // clip rects that are active.
1201  for (; layer; layer = GetNextClippingLayer(layer)) {
1202    if (layer->render_surface() &&
1203        !PointHitsRect(screen_space_point,
1204                       layer->render_surface()->screen_space_transform(),
1205                       layer->render_surface()->content_rect(),
1206                       NULL))
1207      return true;
1208
1209    if (LayerClipsSubtree(layer) &&
1210        !PointHitsRect(screen_space_point,
1211                       layer->screen_space_transform(),
1212                       gfx::Rect(layer->content_bounds()),
1213                       NULL))
1214      return true;
1215  }
1216
1217  // If we have finished walking all ancestors without having already exited,
1218  // then the point is not clipped by any ancestors.
1219  return false;
1220}
1221
1222static bool PointHitsLayer(const LayerImpl* layer,
1223                           const gfx::PointF& screen_space_point,
1224                           float* distance_to_intersection) {
1225  gfx::RectF content_rect(layer->content_bounds());
1226  if (!PointHitsRect(screen_space_point,
1227                     layer->screen_space_transform(),
1228                     content_rect,
1229                     distance_to_intersection))
1230    return false;
1231
1232  // At this point, we think the point does hit the layer, but we need to walk
1233  // up the parents to ensure that the layer was not clipped in such a way
1234  // that the hit point actually should not hit the layer.
1235  if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer))
1236    return false;
1237
1238  // Skip the HUD layer.
1239  if (layer == layer->layer_tree_impl()->hud_layer())
1240    return false;
1241
1242  return true;
1243}
1244
1245struct FindClosestMatchingLayerDataForRecursion {
1246  FindClosestMatchingLayerDataForRecursion()
1247      : closest_match(NULL),
1248        closest_distance(-std::numeric_limits<float>::infinity()) {}
1249  LayerImpl* closest_match;
1250  // Note that the positive z-axis points towards the camera, so bigger means
1251  // closer in this case, counterintuitively.
1252  float closest_distance;
1253};
1254
1255template <typename Functor>
1256static void FindClosestMatchingLayer(
1257    const gfx::PointF& screen_space_point,
1258    LayerImpl* layer,
1259    const Functor& func,
1260    FindClosestMatchingLayerDataForRecursion* data_for_recursion) {
1261  for (int i = layer->children().size() - 1; i >= 0; --i) {
1262    FindClosestMatchingLayer(
1263        screen_space_point, layer->children()[i], func, data_for_recursion);
1264  }
1265
1266  float distance_to_intersection = 0.f;
1267  if (func(layer) &&
1268      PointHitsLayer(layer, screen_space_point, &distance_to_intersection) &&
1269      ((!data_for_recursion->closest_match ||
1270        distance_to_intersection > data_for_recursion->closest_distance))) {
1271    data_for_recursion->closest_distance = distance_to_intersection;
1272    data_for_recursion->closest_match = layer;
1273  }
1274}
1275
1276static bool ScrollsAnyDrawnRenderSurfaceLayerListMember(LayerImpl* layer) {
1277  if (!layer->scrollable())
1278    return false;
1279  if (layer->IsDrawnRenderSurfaceLayerListMember())
1280    return true;
1281  if (!layer->scroll_children())
1282    return false;
1283  for (std::set<LayerImpl*>::const_iterator it =
1284           layer->scroll_children()->begin();
1285       it != layer->scroll_children()->end();
1286       ++it) {
1287    if ((*it)->IsDrawnRenderSurfaceLayerListMember())
1288      return true;
1289  }
1290  return false;
1291}
1292
1293struct FindScrollingLayerFunctor {
1294  bool operator()(LayerImpl* layer) const {
1295    return ScrollsAnyDrawnRenderSurfaceLayerListMember(layer);
1296  }
1297};
1298
1299LayerImpl* LayerTreeImpl::FindFirstScrollingLayerThatIsHitByPoint(
1300    const gfx::PointF& screen_space_point) {
1301  FindClosestMatchingLayerDataForRecursion data_for_recursion;
1302  FindClosestMatchingLayer(screen_space_point,
1303                           root_layer(),
1304                           FindScrollingLayerFunctor(),
1305                           &data_for_recursion);
1306  return data_for_recursion.closest_match;
1307}
1308
1309struct HitTestVisibleScrollableOrTouchableFunctor {
1310  bool operator()(LayerImpl* layer) const {
1311    return layer->IsDrawnRenderSurfaceLayerListMember() ||
1312           ScrollsAnyDrawnRenderSurfaceLayerListMember(layer) ||
1313           !layer->touch_event_handler_region().IsEmpty() ||
1314           layer->have_wheel_event_handlers();
1315  }
1316};
1317
1318LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPoint(
1319    const gfx::PointF& screen_space_point) {
1320  if (!root_layer())
1321    return NULL;
1322  if (!UpdateDrawProperties())
1323    return NULL;
1324  FindClosestMatchingLayerDataForRecursion data_for_recursion;
1325  FindClosestMatchingLayer(screen_space_point,
1326                           root_layer(),
1327                           HitTestVisibleScrollableOrTouchableFunctor(),
1328                           &data_for_recursion);
1329  return data_for_recursion.closest_match;
1330}
1331
1332static bool LayerHasTouchEventHandlersAt(const gfx::PointF& screen_space_point,
1333                                         LayerImpl* layer_impl) {
1334  if (layer_impl->touch_event_handler_region().IsEmpty())
1335    return false;
1336
1337  if (!PointHitsRegion(screen_space_point,
1338                       layer_impl->screen_space_transform(),
1339                       layer_impl->touch_event_handler_region(),
1340                       layer_impl->contents_scale_x(),
1341                       layer_impl->contents_scale_y()))
1342    return false;
1343
1344  // At this point, we think the point does hit the touch event handler region
1345  // on the layer, but we need to walk up the parents to ensure that the layer
1346  // was not clipped in such a way that the hit point actually should not hit
1347  // the layer.
1348  if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer_impl))
1349    return false;
1350
1351  return true;
1352}
1353
1354struct FindTouchEventLayerFunctor {
1355  bool operator()(LayerImpl* layer) const {
1356    return LayerHasTouchEventHandlersAt(screen_space_point, layer);
1357  }
1358  const gfx::PointF screen_space_point;
1359};
1360
1361LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPointInTouchHandlerRegion(
1362    const gfx::PointF& screen_space_point) {
1363  if (!root_layer())
1364    return NULL;
1365  if (!UpdateDrawProperties())
1366    return NULL;
1367  FindTouchEventLayerFunctor func = {screen_space_point};
1368  FindClosestMatchingLayerDataForRecursion data_for_recursion;
1369  FindClosestMatchingLayer(
1370      screen_space_point, root_layer(), func, &data_for_recursion);
1371  return data_for_recursion.closest_match;
1372}
1373
1374void LayerTreeImpl::RegisterSelection(const LayerSelectionBound& start,
1375                                      const LayerSelectionBound& end) {
1376  selection_start_ = start;
1377  selection_end_ = end;
1378}
1379
1380static ViewportSelectionBound ComputeViewportSelection(
1381    const LayerSelectionBound& layer_bound,
1382    LayerImpl* layer,
1383    float device_scale_factor) {
1384  ViewportSelectionBound viewport_bound;
1385  viewport_bound.type = layer_bound.type;
1386
1387  if (!layer || layer_bound.type == SELECTION_BOUND_EMPTY)
1388    return viewport_bound;
1389
1390  gfx::PointF layer_scaled_top = gfx::ScalePoint(layer_bound.edge_top,
1391                                                 layer->contents_scale_x(),
1392                                                 layer->contents_scale_y());
1393  gfx::PointF layer_scaled_bottom = gfx::ScalePoint(layer_bound.edge_bottom,
1394                                                    layer->contents_scale_x(),
1395                                                    layer->contents_scale_y());
1396
1397  bool clipped = false;
1398  gfx::PointF screen_top = MathUtil::MapPoint(
1399      layer->screen_space_transform(), layer_scaled_top, &clipped);
1400  gfx::PointF screen_bottom = MathUtil::MapPoint(
1401      layer->screen_space_transform(), layer_scaled_bottom, &clipped);
1402
1403  const float inv_scale = 1.f / device_scale_factor;
1404  viewport_bound.edge_top = gfx::ScalePoint(screen_top, inv_scale);
1405  viewport_bound.edge_bottom = gfx::ScalePoint(screen_bottom, inv_scale);
1406
1407  // The bottom edge point is used for visibility testing as it is the logical
1408  // focal point for bound selection handles (this may change in the future).
1409  // Shifting the visibility point fractionally inward ensures that neighboring
1410  // or logically coincident layers aligned to integral DPI coordinates will not
1411  // spuriously occlude the bound.
1412  gfx::Vector2dF visibility_offset = layer_scaled_top - layer_scaled_bottom;
1413  visibility_offset.Scale(device_scale_factor / visibility_offset.Length());
1414  gfx::PointF visibility_point = layer_scaled_bottom + visibility_offset;
1415  if (visibility_point.x() <= 0)
1416    visibility_point.set_x(visibility_point.x() + device_scale_factor);
1417  visibility_point = MathUtil::MapPoint(
1418      layer->screen_space_transform(), visibility_point, &clipped);
1419
1420  float intersect_distance = 0.f;
1421  viewport_bound.visible =
1422      PointHitsLayer(layer, visibility_point, &intersect_distance);
1423
1424  return viewport_bound;
1425}
1426
1427void LayerTreeImpl::GetViewportSelection(ViewportSelectionBound* start,
1428                                         ViewportSelectionBound* end) {
1429  DCHECK(start);
1430  DCHECK(end);
1431
1432  *start = ComputeViewportSelection(
1433      selection_start_,
1434      selection_start_.layer_id ? LayerById(selection_start_.layer_id) : NULL,
1435      device_scale_factor());
1436  if (start->type == SELECTION_BOUND_CENTER ||
1437      start->type == SELECTION_BOUND_EMPTY) {
1438    *end = *start;
1439  } else {
1440    *end = ComputeViewportSelection(
1441        selection_end_,
1442        selection_end_.layer_id ? LayerById(selection_end_.layer_id) : NULL,
1443        device_scale_factor());
1444  }
1445}
1446
1447void LayerTreeImpl::RegisterPictureLayerImpl(PictureLayerImpl* layer) {
1448  layer_tree_host_impl_->RegisterPictureLayerImpl(layer);
1449}
1450
1451void LayerTreeImpl::UnregisterPictureLayerImpl(PictureLayerImpl* layer) {
1452  layer_tree_host_impl_->UnregisterPictureLayerImpl(layer);
1453}
1454
1455void LayerTreeImpl::InputScrollAnimationFinished() {
1456  layer_tree_host_impl_->ScrollEnd();
1457}
1458
1459BlockingTaskRunner* LayerTreeImpl::BlockingMainThreadTaskRunner() const {
1460  return proxy()->blocking_main_thread_task_runner();
1461}
1462
1463void LayerTreeImpl::SetPageScaleAnimation(const gfx::Vector2d& target_offset,
1464                                          bool anchor_point,
1465                                          float page_scale,
1466                                          base::TimeDelta duration) {
1467  if (!InnerViewportScrollLayer())
1468    return;
1469
1470  gfx::Vector2dF scroll_total = TotalScrollOffset();
1471  gfx::SizeF scaled_scrollable_size = ScrollableSize();
1472  gfx::SizeF viewport_size = InnerViewportContainerLayer()->bounds();
1473
1474  // Easing constants experimentally determined.
1475  scoped_ptr<TimingFunction> timing_function =
1476      CubicBezierTimingFunction::Create(.8, 0, .3, .9).PassAs<TimingFunction>();
1477
1478  // TODO(miletus) : Pass in ScrollOffset.
1479  page_scale_animation_ = PageScaleAnimation::Create(scroll_total,
1480                                                     total_page_scale_factor(),
1481                                                     viewport_size,
1482                                                     scaled_scrollable_size,
1483                                                     timing_function.Pass());
1484
1485  if (anchor_point) {
1486    gfx::Vector2dF anchor(target_offset);
1487    page_scale_animation_->ZoomWithAnchor(
1488        anchor, page_scale, duration.InSecondsF());
1489  } else {
1490    gfx::Vector2dF scaled_target_offset = target_offset;
1491    page_scale_animation_->ZoomTo(
1492        scaled_target_offset, page_scale, duration.InSecondsF());
1493  }
1494}
1495
1496scoped_ptr<PageScaleAnimation> LayerTreeImpl::TakePageScaleAnimation() {
1497  return page_scale_animation_.Pass();
1498}
1499
1500}  // namespace cc
1501