cc/trees/layer_tree_impl.cc

   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
  34 namespace 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.
  39 class 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::ScrollOffset last_set_scroll_offset() const {
  48     return last_set_scroll_offset_;
  49   }
  50
  51   // LayerScrollOffsetDelegate implementation.
  52   virtual void SetTotalScrollOffset(
  53       const gfx::ScrollOffset& new_offset) override {
  54     last_set_scroll_offset_ = new_offset;
  55     layer_tree_impl_->UpdateScrollOffsetDelegate();
  56   }
  57
  58   virtual gfx::ScrollOffset GetTotalScrollOffset() override {
  59     return layer_tree_impl_->GetDelegatedScrollOffset(layer_);
  60   }
  61
  62   virtual bool IsExternalFlingActive() const override {
  63     return delegate_->IsExternalFlingActive();
  64   }
  65
  66  private:
  67   LayerImpl* layer_;
  68   LayerScrollOffsetDelegate* delegate_;
  69   LayerTreeImpl* layer_tree_impl_;
  70   gfx::ScrollOffset last_set_scroll_offset_;
  71 };
  72
  73 LayerTreeImpl::LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl)
  74     : layer_tree_host_impl_(layer_tree_host_impl),
  75       source_frame_number_(-1),
  76       hud_layer_(0),
  77       currently_scrolling_layer_(NULL),
  78       root_layer_scroll_offset_delegate_(NULL),
  79       background_color_(0),
  80       has_transparent_background_(false),
  81       page_scale_layer_(NULL),
  82       inner_viewport_scroll_layer_(NULL),
  83       outer_viewport_scroll_layer_(NULL),
  84       page_scale_factor_(1),
  85       page_scale_delta_(1),
  86       sent_page_scale_delta_(1),
  87       min_page_scale_factor_(0),
  88       max_page_scale_factor_(0),
  89       scrolling_layer_id_from_previous_tree_(0),
  90       contents_textures_purged_(false),
  91       requires_high_res_to_draw_(false),
  92       viewport_size_invalid_(false),
  93       needs_update_draw_properties_(true),
  94       needs_full_tree_sync_(true),
  95       next_activation_forces_redraw_(false),
  96       has_ever_been_drawn_(false),
  97       render_surface_layer_list_id_(0),
  98       top_controls_layout_height_(0),
  99       top_controls_content_offset_(0),
 100       top_controls_delta_(0),
 101       sent_top_controls_delta_(0) {
 102 }
 103
 104 LayerTreeImpl::~LayerTreeImpl() {
 105   BreakSwapPromises(SwapPromise::SWAP_FAILS);
 106
 107   // Need to explicitly clear the tree prior to destroying this so that
 108   // the LayerTreeImpl pointer is still valid in the LayerImpl dtor.
 109   DCHECK(!root_layer_);
 110   DCHECK(layers_with_copy_output_request_.empty());
 111 }
 112
 113 void LayerTreeImpl::Shutdown() {
 114   root_layer_ = nullptr;
 115 }
 116
 117 void LayerTreeImpl::ReleaseResources() {
 118   if (root_layer_)
 119     ReleaseResourcesRecursive(root_layer_.get());
 120 }
 121
 122 void LayerTreeImpl::SetRootLayer(scoped_ptr<LayerImpl> layer) {
 123   if (inner_viewport_scroll_layer_)
 124     inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 125   if (outer_viewport_scroll_layer_)
 126     outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 127   inner_viewport_scroll_delegate_proxy_ = nullptr;
 128   outer_viewport_scroll_delegate_proxy_ = nullptr;
 129
 130   root_layer_ = layer.Pass();
 131   currently_scrolling_layer_ = NULL;
 132   inner_viewport_scroll_layer_ = NULL;
 133   outer_viewport_scroll_layer_ = NULL;
 134   page_scale_layer_ = NULL;
 135
 136   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 137 }
 138
 139 LayerImpl* LayerTreeImpl::InnerViewportScrollLayer() const {
 140   return inner_viewport_scroll_layer_;
 141 }
 142
 143 LayerImpl* LayerTreeImpl::OuterViewportScrollLayer() const {
 144   return outer_viewport_scroll_layer_;
 145 }
 146
 147 gfx::ScrollOffset LayerTreeImpl::TotalScrollOffset() const {
 148   gfx::ScrollOffset offset;
 149
 150   if (inner_viewport_scroll_layer_)
 151     offset += inner_viewport_scroll_layer_->TotalScrollOffset();
 152
 153   if (outer_viewport_scroll_layer_)
 154     offset += outer_viewport_scroll_layer_->TotalScrollOffset();
 155
 156   return offset;
 157 }
 158
 159 gfx::ScrollOffset LayerTreeImpl::TotalMaxScrollOffset() const {
 160   gfx::ScrollOffset offset;
 161
 162   if (inner_viewport_scroll_layer_)
 163     offset += inner_viewport_scroll_layer_->MaxScrollOffset();
 164
 165   if (outer_viewport_scroll_layer_)
 166     offset += outer_viewport_scroll_layer_->MaxScrollOffset();
 167
 168   return offset;
 169 }
 170 gfx::Vector2dF LayerTreeImpl::TotalScrollDelta() const {
 171   DCHECK(inner_viewport_scroll_layer_);
 172   gfx::Vector2dF delta = inner_viewport_scroll_layer_->ScrollDelta();
 173
 174   if (outer_viewport_scroll_layer_)
 175     delta += outer_viewport_scroll_layer_->ScrollDelta();
 176
 177   return delta;
 178 }
 179
 180 scoped_ptr<LayerImpl> LayerTreeImpl::DetachLayerTree() {
 181   // Clear all data structures that have direct references to the layer tree.
 182   scrolling_layer_id_from_previous_tree_ =
 183     currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0;
 184   if (inner_viewport_scroll_layer_)
 185     inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 186   if (outer_viewport_scroll_layer_)
 187     outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 188   inner_viewport_scroll_delegate_proxy_ = nullptr;
 189   outer_viewport_scroll_delegate_proxy_ = nullptr;
 190   inner_viewport_scroll_layer_ = NULL;
 191   outer_viewport_scroll_layer_ = NULL;
 192   page_scale_layer_ = NULL;
 193   currently_scrolling_layer_ = NULL;
 194
 195   render_surface_layer_list_.clear();
 196   set_needs_update_draw_properties();
 197   return root_layer_.Pass();
 198 }
 199
 200 void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
 201   // The request queue should have been processed and does not require a push.
 202   DCHECK_EQ(ui_resource_request_queue_.size(), 0u);
 203
 204   if (next_activation_forces_redraw_) {
 205     target_tree->ForceRedrawNextActivation();
 206     next_activation_forces_redraw_ = false;
 207   }
 208
 209   target_tree->PassSwapPromises(&swap_promise_list_);
 210
 211   target_tree->top_controls_layout_height_ = top_controls_layout_height_;
 212   target_tree->top_controls_content_offset_ = top_controls_content_offset_;
 213   target_tree->top_controls_delta_ =
 214       target_tree->top_controls_delta_ -
 215           target_tree->sent_top_controls_delta_;
 216   target_tree->sent_top_controls_delta_ = 0.f;
 217
 218   target_tree->SetPageScaleValues(
 219       page_scale_factor(), min_page_scale_factor(), max_page_scale_factor(),
 220       target_tree->page_scale_delta() / target_tree->sent_page_scale_delta());
 221   target_tree->set_sent_page_scale_delta(1);
 222
 223   target_tree->page_scale_animation_ = page_scale_animation_.Pass();
 224
 225   if (page_scale_layer_ && inner_viewport_scroll_layer_) {
 226     target_tree->SetViewportLayersFromIds(
 227         page_scale_layer_->id(),
 228         inner_viewport_scroll_layer_->id(),
 229         outer_viewport_scroll_layer_ ? outer_viewport_scroll_layer_->id()
 230                                      : Layer::INVALID_ID);
 231   } else {
 232     target_tree->ClearViewportLayers();
 233   }
 234
 235   target_tree->RegisterSelection(selection_start_, selection_end_);
 236
 237   // This should match the property synchronization in
 238   // LayerTreeHost::finishCommitOnImplThread().
 239   target_tree->set_source_frame_number(source_frame_number());
 240   target_tree->set_background_color(background_color());
 241   target_tree->set_has_transparent_background(has_transparent_background());
 242
 243   if (ContentsTexturesPurged())
 244     target_tree->SetContentsTexturesPurged();
 245   else
 246     target_tree->ResetContentsTexturesPurged();
 247
 248   if (ViewportSizeInvalid())
 249     target_tree->SetViewportSizeInvalid();
 250   else
 251     target_tree->ResetViewportSizeInvalid();
 252
 253   if (hud_layer())
 254     target_tree->set_hud_layer(static_cast<HeadsUpDisplayLayerImpl*>(
 255         LayerTreeHostCommon::FindLayerInSubtree(
 256             target_tree->root_layer(), hud_layer()->id())));
 257   else
 258     target_tree->set_hud_layer(NULL);
 259
 260   target_tree->has_ever_been_drawn_ = false;
 261 }
 262
 263 LayerImpl* LayerTreeImpl::InnerViewportContainerLayer() const {
 264   return inner_viewport_scroll_layer_
 265              ? inner_viewport_scroll_layer_->scroll_clip_layer()
 266              : NULL;
 267 }
 268
 269 LayerImpl* LayerTreeImpl::CurrentlyScrollingLayer() const {
 270   DCHECK(IsActiveTree());
 271   return currently_scrolling_layer_;
 272 }
 273
 274 void LayerTreeImpl::SetCurrentlyScrollingLayer(LayerImpl* layer) {
 275   if (currently_scrolling_layer_ == layer)
 276     return;
 277
 278   if (currently_scrolling_layer_ &&
 279       currently_scrolling_layer_->scrollbar_animation_controller())
 280     currently_scrolling_layer_->scrollbar_animation_controller()
 281         ->DidScrollEnd();
 282   currently_scrolling_layer_ = layer;
 283   if (layer && layer->scrollbar_animation_controller())
 284     layer->scrollbar_animation_controller()->DidScrollBegin();
 285 }
 286
 287 void LayerTreeImpl::ClearCurrentlyScrollingLayer() {
 288   SetCurrentlyScrollingLayer(NULL);
 289   scrolling_layer_id_from_previous_tree_ = 0;
 290 }
 291
 292 namespace {
 293
 294 void ForceScrollbarParameterUpdateAfterScaleChange(LayerImpl* current_layer) {
 295   if (!current_layer)
 296     return;
 297
 298   while (current_layer) {
 299     current_layer->ScrollbarParametersDidChange();
 300     current_layer = current_layer->parent();
 301   }
 302 }
 303
 304 }  // namespace
 305
 306 void LayerTreeImpl::SetPageScaleFactorAndLimits(float page_scale_factor,
 307     float min_page_scale_factor, float max_page_scale_factor) {
 308   SetPageScaleValues(page_scale_factor, min_page_scale_factor,
 309       max_page_scale_factor, page_scale_delta_);
 310 }
 311
 312 void LayerTreeImpl::SetPageScaleDelta(float delta) {
 313   SetPageScaleValues(page_scale_factor_, min_page_scale_factor_,
 314       max_page_scale_factor_, delta);
 315 }
 316
 317 void LayerTreeImpl::SetPageScaleValues(float page_scale_factor,
 318       float min_page_scale_factor, float max_page_scale_factor,
 319       float page_scale_delta) {
 320   bool page_scale_changed =
 321       min_page_scale_factor != min_page_scale_factor_ ||
 322       max_page_scale_factor != max_page_scale_factor_ ||
 323       page_scale_factor != page_scale_factor_;
 324
 325   min_page_scale_factor_ = min_page_scale_factor;
 326   max_page_scale_factor_ = max_page_scale_factor;
 327   page_scale_factor_ = page_scale_factor;
 328
 329   float total = page_scale_factor_ * page_scale_delta;
 330   if (min_page_scale_factor_ && total < min_page_scale_factor_)
 331     page_scale_delta = min_page_scale_factor_ / page_scale_factor_;
 332   else if (max_page_scale_factor_ && total > max_page_scale_factor_)
 333     page_scale_delta = max_page_scale_factor_ / page_scale_factor_;
 334
 335   if (page_scale_delta_ == page_scale_delta && !page_scale_changed)
 336     return;
 337
 338   if (page_scale_delta_ != page_scale_delta) {
 339     page_scale_delta_ = page_scale_delta;
 340
 341     if (IsActiveTree()) {
 342       LayerTreeImpl* pending_tree = layer_tree_host_impl_->pending_tree();
 343       if (pending_tree) {
 344         DCHECK_EQ(1, pending_tree->sent_page_scale_delta());
 345         pending_tree->SetPageScaleDelta(
 346             page_scale_delta_ / sent_page_scale_delta_);
 347       }
 348     }
 349
 350     set_needs_update_draw_properties();
 351   }
 352
 353   if (root_layer_scroll_offset_delegate_) {
 354     root_layer_scroll_offset_delegate_->UpdateRootLayerState(
 355         TotalScrollOffset(),
 356         TotalMaxScrollOffset(),
 357         ScrollableSize(),
 358         total_page_scale_factor(),
 359         min_page_scale_factor_,
 360         max_page_scale_factor_);
 361   }
 362
 363   ForceScrollbarParameterUpdateAfterScaleChange(page_scale_layer());
 364 }
 365
 366 gfx::SizeF LayerTreeImpl::ScrollableViewportSize() const {
 367   if (!InnerViewportContainerLayer())
 368     return gfx::SizeF();
 369
 370   return gfx::ScaleSize(InnerViewportContainerLayer()->bounds(),
 371                         1.0f / total_page_scale_factor());
 372 }
 373
 374 gfx::Rect LayerTreeImpl::RootScrollLayerDeviceViewportBounds() const {
 375   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
 376                                      ? OuterViewportScrollLayer()
 377                                      : InnerViewportScrollLayer();
 378   if (!root_scroll_layer || root_scroll_layer->children().empty())
 379     return gfx::Rect();
 380   LayerImpl* layer = root_scroll_layer->children()[0];
 381   return MathUtil::MapEnclosingClippedRect(layer->screen_space_transform(),
 382                                            gfx::Rect(layer->content_bounds()));
 383 }
 384
 385 static void ApplySentScrollDeltasFromAbortedCommitTo(LayerImpl* layer) {
 386   layer->ApplySentScrollDeltasFromAbortedCommit();
 387 }
 388
 389 void LayerTreeImpl::ApplySentScrollAndScaleDeltasFromAbortedCommit() {
 390   DCHECK(IsActiveTree());
 391
 392   page_scale_factor_ *= sent_page_scale_delta_;
 393   page_scale_delta_ /= sent_page_scale_delta_;
 394   sent_page_scale_delta_ = 1.f;
 395
 396   top_controls_content_offset_ += sent_top_controls_delta_;
 397   top_controls_delta_ -= sent_top_controls_delta_;
 398   sent_top_controls_delta_ = 0.f;
 399
 400   if (!root_layer())
 401     return;
 402
 403   LayerTreeHostCommon::CallFunctionForSubtree(
 404       root_layer(), base::Bind(&ApplySentScrollDeltasFromAbortedCommitTo));
 405 }
 406
 407 static void ApplyScrollDeltasSinceBeginMainFrameTo(LayerImpl* layer) {
 408   layer->ApplyScrollDeltasSinceBeginMainFrame();
 409 }
 410
 411 void LayerTreeImpl::ApplyScrollDeltasSinceBeginMainFrame() {
 412   DCHECK(IsPendingTree());
 413   if (!root_layer())
 414     return;
 415
 416   LayerTreeHostCommon::CallFunctionForSubtree(
 417       root_layer(), base::Bind(&ApplyScrollDeltasSinceBeginMainFrameTo));
 418 }
 419
 420 void LayerTreeImpl::SetViewportLayersFromIds(
 421     int page_scale_layer_id,
 422     int inner_viewport_scroll_layer_id,
 423     int outer_viewport_scroll_layer_id) {
 424   page_scale_layer_ = LayerById(page_scale_layer_id);
 425   DCHECK(page_scale_layer_);
 426
 427   inner_viewport_scroll_layer_ =
 428       LayerById(inner_viewport_scroll_layer_id);
 429   DCHECK(inner_viewport_scroll_layer_);
 430
 431   outer_viewport_scroll_layer_ =
 432       LayerById(outer_viewport_scroll_layer_id);
 433   DCHECK(outer_viewport_scroll_layer_ ||
 434          outer_viewport_scroll_layer_id == Layer::INVALID_ID);
 435
 436   if (!root_layer_scroll_offset_delegate_)
 437     return;
 438
 439   inner_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 440       new LayerScrollOffsetDelegateProxy(inner_viewport_scroll_layer_,
 441                                          root_layer_scroll_offset_delegate_,
 442                                          this));
 443
 444   if (outer_viewport_scroll_layer_)
 445     outer_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 446         new LayerScrollOffsetDelegateProxy(outer_viewport_scroll_layer_,
 447                                            root_layer_scroll_offset_delegate_,
 448                                            this));
 449 }
 450
 451 void LayerTreeImpl::ClearViewportLayers() {
 452   page_scale_layer_ = NULL;
 453   inner_viewport_scroll_layer_ = NULL;
 454   outer_viewport_scroll_layer_ = NULL;
 455 }
 456
 457 bool LayerTreeImpl::UpdateDrawProperties() {
 458   if (!needs_update_draw_properties_)
 459     return true;
 460
 461   // For max_texture_size.
 462   if (!layer_tree_host_impl_->renderer())
 463     return false;
 464
 465   if (!root_layer())
 466     return false;
 467
 468   needs_update_draw_properties_ = false;
 469   render_surface_layer_list_.clear();
 470
 471   {
 472     TRACE_EVENT2("cc",
 473                  "LayerTreeImpl::UpdateDrawProperties",
 474                  "IsActive",
 475                  IsActiveTree(),
 476                  "SourceFrameNumber",
 477                  source_frame_number_);
 478     LayerImpl* page_scale_layer =
 479         page_scale_layer_ ? page_scale_layer_ : InnerViewportContainerLayer();
 480     bool can_render_to_separate_surface =
 481         (layer_tree_host_impl_->GetDrawMode() !=
 482          DRAW_MODE_RESOURCELESS_SOFTWARE);
 483
 484     ++render_surface_layer_list_id_;
 485     LayerTreeHostCommon::CalcDrawPropsImplInputs inputs(
 486         root_layer(),
 487         DrawViewportSize(),
 488         layer_tree_host_impl_->DrawTransform(),
 489         device_scale_factor(),
 490         total_page_scale_factor(),
 491         page_scale_layer,
 492         resource_provider()->max_texture_size(),
 493         settings().can_use_lcd_text,
 494         can_render_to_separate_surface,
 495         settings().layer_transforms_should_scale_layer_contents,
 496         &render_surface_layer_list_,
 497         render_surface_layer_list_id_);
 498     LayerTreeHostCommon::CalculateDrawProperties(&inputs);
 499   }
 500
 501   {
 502     TRACE_EVENT2("cc",
 503                  "LayerTreeImpl::UpdateTilePriorities",
 504                  "IsActive",
 505                  IsActiveTree(),
 506                  "SourceFrameNumber",
 507                  source_frame_number_);
 508     scoped_ptr<OcclusionTracker<LayerImpl> > occlusion_tracker;
 509     if (settings().use_occlusion_for_tile_prioritization) {
 510       occlusion_tracker.reset(new OcclusionTracker<LayerImpl>(
 511           root_layer()->render_surface()->content_rect()));
 512       occlusion_tracker->set_minimum_tracking_size(
 513           settings().minimum_occlusion_tracking_size);
 514     }
 515
 516     bool resourceless_software_draw = (layer_tree_host_impl_->GetDrawMode() ==
 517                                        DRAW_MODE_RESOURCELESS_SOFTWARE);
 518
 519     // LayerIterator is used here instead of CallFunctionForSubtree to only
 520     // UpdateTilePriorities on layers that will be visible (and thus have valid
 521     // draw properties) and not because any ordering is required.
 522     typedef LayerIterator<LayerImpl> LayerIteratorType;
 523     LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
 524     for (LayerIteratorType it =
 525              LayerIteratorType::Begin(&render_surface_layer_list_);
 526          it != end;
 527          ++it) {
 528       if (occlusion_tracker)
 529         occlusion_tracker->EnterLayer(it);
 530
 531       LayerImpl* layer = *it;
 532       const Occlusion& occlusion_in_content_space =
 533           occlusion_tracker ? occlusion_tracker->GetCurrentOcclusionForLayer(
 534                                   layer->draw_transform())
 535                             : Occlusion();
 536
 537       if (it.represents_itself()) {
 538         layer->UpdateTiles(occlusion_in_content_space,
 539                            resourceless_software_draw);
 540       }
 541
 542       if (!it.represents_contributing_render_surface()) {
 543         if (occlusion_tracker)
 544           occlusion_tracker->LeaveLayer(it);
 545         continue;
 546       }
 547
 548       if (layer->mask_layer()) {
 549         layer->mask_layer()->UpdateTiles(occlusion_in_content_space,
 550                                          resourceless_software_draw);
 551       }
 552       if (layer->replica_layer() && layer->replica_layer()->mask_layer()) {
 553         layer->replica_layer()->mask_layer()->UpdateTiles(
 554             occlusion_in_content_space, resourceless_software_draw);
 555       }
 556
 557       if (occlusion_tracker)
 558         occlusion_tracker->LeaveLayer(it);
 559     }
 560   }
 561
 562   DCHECK(!needs_update_draw_properties_) <<
 563       "CalcDrawProperties should not set_needs_update_draw_properties()";
 564   return true;
 565 }
 566
 567 const LayerImplList& LayerTreeImpl::RenderSurfaceLayerList() const {
 568   // If this assert triggers, then the list is dirty.
 569   DCHECK(!needs_update_draw_properties_);
 570   return render_surface_layer_list_;
 571 }
 572
 573 gfx::SizeF LayerTreeImpl::ScrollableSize() const {
 574   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
 575                                      ? OuterViewportScrollLayer()
 576                                      : InnerViewportScrollLayer();
 577   if (!root_scroll_layer || root_scroll_layer->children().empty())
 578     return gfx::SizeF();
 579   return root_scroll_layer->children()[0]->bounds();
 580 }
 581
 582 LayerImpl* LayerTreeImpl::LayerById(int id) {
 583   LayerIdMap::iterator iter = layer_id_map_.find(id);
 584   return iter != layer_id_map_.end() ? iter->second : NULL;
 585 }
 586
 587 void LayerTreeImpl::RegisterLayer(LayerImpl* layer) {
 588   DCHECK(!LayerById(layer->id()));
 589   layer_id_map_[layer->id()] = layer;
 590 }
 591
 592 void LayerTreeImpl::UnregisterLayer(LayerImpl* layer) {
 593   DCHECK(LayerById(layer->id()));
 594   layer_id_map_.erase(layer->id());
 595 }
 596
 597 size_t LayerTreeImpl::NumLayers() {
 598   return layer_id_map_.size();
 599 }
 600
 601 void LayerTreeImpl::PushPersistedState(LayerTreeImpl* pending_tree) {
 602   pending_tree->SetCurrentlyScrollingLayer(
 603       LayerTreeHostCommon::FindLayerInSubtree(pending_tree->root_layer(),
 604           currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0));
 605 }
 606
 607 static void DidBecomeActiveRecursive(LayerImpl* layer) {
 608   layer->DidBecomeActive();
 609   if (layer->mask_layer())
 610     layer->mask_layer()->DidBecomeActive();
 611   if (layer->replica_layer() && layer->replica_layer()->mask_layer())
 612     layer->replica_layer()->mask_layer()->DidBecomeActive();
 613
 614   for (size_t i = 0; i < layer->children().size(); ++i)
 615     DidBecomeActiveRecursive(layer->children()[i]);
 616 }
 617
 618 void LayerTreeImpl::DidBecomeActive() {
 619   if (next_activation_forces_redraw_) {
 620     layer_tree_host_impl_->SetFullRootLayerDamage();
 621     next_activation_forces_redraw_ = false;
 622   }
 623
 624   if (scrolling_layer_id_from_previous_tree_) {
 625     currently_scrolling_layer_ = LayerTreeHostCommon::FindLayerInSubtree(
 626         root_layer(), scrolling_layer_id_from_previous_tree_);
 627   }
 628
 629   // Always reset this flag on activation, as we would only have activated
 630   // if we were in a good state.
 631   ResetRequiresHighResToDraw();
 632
 633   if (root_layer())
 634     DidBecomeActiveRecursive(root_layer());
 635
 636   devtools_instrumentation::DidActivateLayerTree(layer_tree_host_impl_->id(),
 637                                                  source_frame_number_);
 638 }
 639
 640 bool LayerTreeImpl::ContentsTexturesPurged() const {
 641   return contents_textures_purged_;
 642 }
 643
 644 void LayerTreeImpl::SetContentsTexturesPurged() {
 645   if (contents_textures_purged_)
 646     return;
 647   contents_textures_purged_ = true;
 648   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 649 }
 650
 651 void LayerTreeImpl::ResetContentsTexturesPurged() {
 652   if (!contents_textures_purged_)
 653     return;
 654   contents_textures_purged_ = false;
 655   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 656 }
 657
 658 void LayerTreeImpl::SetRequiresHighResToDraw() {
 659   requires_high_res_to_draw_ = true;
 660 }
 661
 662 void LayerTreeImpl::ResetRequiresHighResToDraw() {
 663   requires_high_res_to_draw_ = false;
 664 }
 665
 666 bool LayerTreeImpl::RequiresHighResToDraw() const {
 667   return requires_high_res_to_draw_;
 668 }
 669
 670 bool LayerTreeImpl::ViewportSizeInvalid() const {
 671   return viewport_size_invalid_;
 672 }
 673
 674 void LayerTreeImpl::SetViewportSizeInvalid() {
 675   viewport_size_invalid_ = true;
 676   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 677 }
 678
 679 void LayerTreeImpl::ResetViewportSizeInvalid() {
 680   viewport_size_invalid_ = false;
 681   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 682 }
 683
 684 Proxy* LayerTreeImpl::proxy() const {
 685   return layer_tree_host_impl_->proxy();
 686 }
 687
 688 const LayerTreeSettings& LayerTreeImpl::settings() const {
 689   return layer_tree_host_impl_->settings();
 690 }
 691
 692 const RendererCapabilitiesImpl& LayerTreeImpl::GetRendererCapabilities() const {
 693   return layer_tree_host_impl_->GetRendererCapabilities();
 694 }
 695
 696 ContextProvider* LayerTreeImpl::context_provider() const {
 697   return output_surface()->context_provider();
 698 }
 699
 700 OutputSurface* LayerTreeImpl::output_surface() const {
 701   return layer_tree_host_impl_->output_surface();
 702 }
 703
 704 ResourceProvider* LayerTreeImpl::resource_provider() const {
 705   return layer_tree_host_impl_->resource_provider();
 706 }
 707
 708 TileManager* LayerTreeImpl::tile_manager() const {
 709   return layer_tree_host_impl_->tile_manager();
 710 }
 711
 712 FrameRateCounter* LayerTreeImpl::frame_rate_counter() const {
 713   return layer_tree_host_impl_->fps_counter();
 714 }
 715
 716 PaintTimeCounter* LayerTreeImpl::paint_time_counter() const {
 717   return layer_tree_host_impl_->paint_time_counter();
 718 }
 719
 720 MemoryHistory* LayerTreeImpl::memory_history() const {
 721   return layer_tree_host_impl_->memory_history();
 722 }
 723
 724 gfx::Size LayerTreeImpl::device_viewport_size() const {
 725   return layer_tree_host_impl_->device_viewport_size();
 726 }
 727
 728 bool LayerTreeImpl::IsActiveTree() const {
 729   return layer_tree_host_impl_->active_tree() == this;
 730 }
 731
 732 bool LayerTreeImpl::IsPendingTree() const {
 733   return layer_tree_host_impl_->pending_tree() == this;
 734 }
 735
 736 bool LayerTreeImpl::IsRecycleTree() const {
 737   return layer_tree_host_impl_->recycle_tree() == this;
 738 }
 739
 740 LayerImpl* LayerTreeImpl::FindActiveTreeLayerById(int id) {
 741   LayerTreeImpl* tree = layer_tree_host_impl_->active_tree();
 742   if (!tree)
 743     return NULL;
 744   return tree->LayerById(id);
 745 }
 746
 747 LayerImpl* LayerTreeImpl::FindPendingTreeLayerById(int id) {
 748   LayerTreeImpl* tree = layer_tree_host_impl_->pending_tree();
 749   if (!tree)
 750     return NULL;
 751   return tree->LayerById(id);
 752 }
 753
 754 LayerImpl* LayerTreeImpl::FindRecycleTreeLayerById(int id) {
 755   LayerTreeImpl* tree = layer_tree_host_impl_->recycle_tree();
 756   if (!tree)
 757     return NULL;
 758   return tree->LayerById(id);
 759 }
 760
 761 bool LayerTreeImpl::PinchGestureActive() const {
 762   return layer_tree_host_impl_->pinch_gesture_active();
 763 }
 764
 765 BeginFrameArgs LayerTreeImpl::CurrentBeginFrameArgs() const {
 766   return layer_tree_host_impl_->CurrentBeginFrameArgs();
 767 }
 768
 769 base::TimeDelta LayerTreeImpl::begin_impl_frame_interval() const {
 770   return layer_tree_host_impl_->begin_impl_frame_interval();
 771 }
 772
 773 void LayerTreeImpl::SetNeedsCommit() {
 774   layer_tree_host_impl_->SetNeedsCommit();
 775 }
 776
 777 gfx::Rect LayerTreeImpl::DeviceViewport() const {
 778   return layer_tree_host_impl_->DeviceViewport();
 779 }
 780
 781 gfx::Size LayerTreeImpl::DrawViewportSize() const {
 782   return layer_tree_host_impl_->DrawViewportSize();
 783 }
 784
 785 const gfx::Rect LayerTreeImpl::ViewportRectForTilePriority() const {
 786   return layer_tree_host_impl_->ViewportRectForTilePriority();
 787 }
 788
 789 scoped_ptr<ScrollbarAnimationController>
 790 LayerTreeImpl::CreateScrollbarAnimationController(LayerImpl* scrolling_layer) {
 791   DCHECK(settings().scrollbar_fade_delay_ms);
 792   DCHECK(settings().scrollbar_fade_duration_ms);
 793   base::TimeDelta delay =
 794       base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_delay_ms);
 795   base::TimeDelta duration =
 796       base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_duration_ms);
 797   switch (settings().scrollbar_animator) {
 798     case LayerTreeSettings::LinearFade: {
 799       return ScrollbarAnimationControllerLinearFade::Create(
 800           scrolling_layer, layer_tree_host_impl_, delay, duration);
 801     }
 802     case LayerTreeSettings::Thinning: {
 803       return ScrollbarAnimationControllerThinning::Create(
 804           scrolling_layer, layer_tree_host_impl_, delay, duration);
 805     }
 806     case LayerTreeSettings::NoAnimator:
 807       NOTREACHED();
 808       break;
 809   }
 810   return nullptr;
 811 }
 812
 813 void LayerTreeImpl::DidAnimateScrollOffset() {
 814   layer_tree_host_impl_->DidAnimateScrollOffset();
 815 }
 816
 817 bool LayerTreeImpl::use_gpu_rasterization() const {
 818   return layer_tree_host_impl_->use_gpu_rasterization();
 819 }
 820
 821 bool LayerTreeImpl::create_low_res_tiling() const {
 822   return layer_tree_host_impl_->create_low_res_tiling();
 823 }
 824
 825 void LayerTreeImpl::SetNeedsRedraw() {
 826   layer_tree_host_impl_->SetNeedsRedraw();
 827 }
 828
 829 const LayerTreeDebugState& LayerTreeImpl::debug_state() const {
 830   return layer_tree_host_impl_->debug_state();
 831 }
 832
 833 float LayerTreeImpl::device_scale_factor() const {
 834   return layer_tree_host_impl_->device_scale_factor();
 835 }
 836
 837 DebugRectHistory* LayerTreeImpl::debug_rect_history() const {
 838   return layer_tree_host_impl_->debug_rect_history();
 839 }
 840
 841 AnimationRegistrar* LayerTreeImpl::animationRegistrar() const {
 842   return layer_tree_host_impl_->animation_registrar();
 843 }
 844
 845 void LayerTreeImpl::GetAllTilesForTracing(std::set<const Tile*>* tiles) const {
 846   typedef LayerIterator<LayerImpl> LayerIteratorType;
 847   LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
 848   for (LayerIteratorType it =
 849            LayerIteratorType::Begin(&render_surface_layer_list_);
 850        it != end;
 851        ++it) {
 852     if (!it.represents_itself())
 853       continue;
 854     LayerImpl* layer_impl = *it;
 855     layer_impl->GetAllTilesForTracing(tiles);
 856   }
 857 }
 858
 859 void LayerTreeImpl::AsValueInto(base::debug::TracedValue* state) const {
 860   TracedValue::MakeDictIntoImplicitSnapshot(state, "cc::LayerTreeImpl", this);
 861   state->SetInteger("source_frame_number", source_frame_number_);
 862
 863   state->BeginDictionary("root_layer");
 864   root_layer_->AsValueInto(state);
 865   state->EndDictionary();
 866
 867   state->BeginArray("render_surface_layer_list");
 868   typedef LayerIterator<LayerImpl> LayerIteratorType;
 869   LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
 870   for (LayerIteratorType it = LayerIteratorType::Begin(
 871            &render_surface_layer_list_); it != end; ++it) {
 872     if (!it.represents_itself())
 873       continue;
 874     TracedValue::AppendIDRef(*it, state);
 875   }
 876   state->EndArray();
 877
 878   state->BeginArray("swap_promise_trace_ids");
 879   for (size_t i = 0; i < swap_promise_list_.size(); i++)
 880     state->AppendDouble(swap_promise_list_[i]->TraceId());
 881   state->EndArray();
 882 }
 883
 884 void LayerTreeImpl::SetRootLayerScrollOffsetDelegate(
 885     LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate) {
 886   if (root_layer_scroll_offset_delegate_ == root_layer_scroll_offset_delegate)
 887     return;
 888
 889   if (!root_layer_scroll_offset_delegate) {
 890     // Make sure we remove the proxies from their layers before
 891     // releasing them.
 892     if (InnerViewportScrollLayer())
 893       InnerViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
 894     if (OuterViewportScrollLayer())
 895       OuterViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
 896     inner_viewport_scroll_delegate_proxy_ = nullptr;
 897     outer_viewport_scroll_delegate_proxy_ = nullptr;
 898   }
 899
 900   root_layer_scroll_offset_delegate_ = root_layer_scroll_offset_delegate;
 901
 902   if (root_layer_scroll_offset_delegate_) {
 903     root_layer_scroll_offset_delegate_->UpdateRootLayerState(
 904         TotalScrollOffset(),
 905         TotalMaxScrollOffset(),
 906         ScrollableSize(),
 907         total_page_scale_factor(),
 908         min_page_scale_factor(),
 909         max_page_scale_factor());
 910
 911     if (inner_viewport_scroll_layer_) {
 912       inner_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 913           new LayerScrollOffsetDelegateProxy(InnerViewportScrollLayer(),
 914                                              root_layer_scroll_offset_delegate_,
 915                                              this));
 916       inner_viewport_scroll_layer_->SetScrollOffsetDelegate(
 917           inner_viewport_scroll_delegate_proxy_.get());
 918     }
 919
 920     if (outer_viewport_scroll_layer_) {
 921       outer_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 922           new LayerScrollOffsetDelegateProxy(OuterViewportScrollLayer(),
 923                                              root_layer_scroll_offset_delegate_,
 924                                              this));
 925       outer_viewport_scroll_layer_->SetScrollOffsetDelegate(
 926           outer_viewport_scroll_delegate_proxy_.get());
 927     }
 928   }
 929 }
 930
 931 void LayerTreeImpl::UpdateScrollOffsetDelegate() {
 932   DCHECK(InnerViewportScrollLayer());
 933   DCHECK(root_layer_scroll_offset_delegate_);
 934
 935   gfx::ScrollOffset offset =
 936       inner_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
 937
 938   if (OuterViewportScrollLayer())
 939     offset += outer_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
 940
 941   root_layer_scroll_offset_delegate_->UpdateRootLayerState(
 942       offset,
 943       TotalMaxScrollOffset(),
 944       ScrollableSize(),
 945       total_page_scale_factor(),
 946       min_page_scale_factor(),
 947       max_page_scale_factor());
 948 }
 949
 950 gfx::ScrollOffset LayerTreeImpl::GetDelegatedScrollOffset(LayerImpl* layer) {
 951   DCHECK(root_layer_scroll_offset_delegate_);
 952   DCHECK(InnerViewportScrollLayer());
 953   if (layer == InnerViewportScrollLayer() && !OuterViewportScrollLayer())
 954     return root_layer_scroll_offset_delegate_->GetTotalScrollOffset();
 955
 956   // If we get here, we have both inner/outer viewports, and need to distribute
 957   // the scroll offset between them.
 958   DCHECK(inner_viewport_scroll_delegate_proxy_);
 959   DCHECK(outer_viewport_scroll_delegate_proxy_);
 960   gfx::ScrollOffset inner_viewport_offset =
 961       inner_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
 962   gfx::ScrollOffset outer_viewport_offset =
 963       outer_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
 964
 965   // It may be nothing has changed.
 966   gfx::ScrollOffset delegate_offset =
 967       root_layer_scroll_offset_delegate_->GetTotalScrollOffset();
 968   if (inner_viewport_offset + outer_viewport_offset == delegate_offset) {
 969     if (layer == InnerViewportScrollLayer())
 970       return inner_viewport_offset;
 971     else
 972       return outer_viewport_offset;
 973   }
 974
 975   gfx::ScrollOffset max_outer_viewport_scroll_offset =
 976       OuterViewportScrollLayer()->MaxScrollOffset();
 977
 978   outer_viewport_offset = delegate_offset - inner_viewport_offset;
 979   outer_viewport_offset.SetToMin(max_outer_viewport_scroll_offset);
 980   outer_viewport_offset.SetToMax(gfx::ScrollOffset());
 981
 982   if (layer == OuterViewportScrollLayer())
 983     return outer_viewport_offset;
 984
 985   inner_viewport_offset = delegate_offset - outer_viewport_offset;
 986
 987   return inner_viewport_offset;
 988 }
 989
 990 void LayerTreeImpl::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {
 991   DCHECK(swap_promise);
 992   swap_promise_list_.push_back(swap_promise.Pass());
 993 }
 994
 995 void LayerTreeImpl::PassSwapPromises(
 996     ScopedPtrVector<SwapPromise>* new_swap_promise) {
 997   swap_promise_list_.insert_and_take(swap_promise_list_.end(),
 998                                      new_swap_promise);
 999   new_swap_promise->clear();
1000 }
1001
1002 void LayerTreeImpl::FinishSwapPromises(CompositorFrameMetadata* metadata) {
1003   for (size_t i = 0; i < swap_promise_list_.size(); i++)
1004     swap_promise_list_[i]->DidSwap(metadata);
1005   swap_promise_list_.clear();
1006 }
1007
1008 void LayerTreeImpl::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
1009   for (size_t i = 0; i < swap_promise_list_.size(); i++)
1010     swap_promise_list_[i]->DidNotSwap(reason);
1011   swap_promise_list_.clear();
1012 }
1013
1014 void LayerTreeImpl::DidModifyTilePriorities() {
1015   layer_tree_host_impl_->DidModifyTilePriorities();
1016 }
1017
1018 void LayerTreeImpl::set_ui_resource_request_queue(
1019     const UIResourceRequestQueue& queue) {
1020   ui_resource_request_queue_ = queue;
1021 }
1022
1023 ResourceProvider::ResourceId LayerTreeImpl::ResourceIdForUIResource(
1024     UIResourceId uid) const {
1025   return layer_tree_host_impl_->ResourceIdForUIResource(uid);
1026 }
1027
1028 bool LayerTreeImpl::IsUIResourceOpaque(UIResourceId uid) const {
1029   return layer_tree_host_impl_->IsUIResourceOpaque(uid);
1030 }
1031
1032 void LayerTreeImpl::ProcessUIResourceRequestQueue() {
1033   while (ui_resource_request_queue_.size() > 0) {
1034     UIResourceRequest req = ui_resource_request_queue_.front();
1035     ui_resource_request_queue_.pop_front();
1036
1037     switch (req.GetType()) {
1038       case UIResourceRequest::UIResourceCreate:
1039         layer_tree_host_impl_->CreateUIResource(req.GetId(), req.GetBitmap());
1040         break;
1041       case UIResourceRequest::UIResourceDelete:
1042         layer_tree_host_impl_->DeleteUIResource(req.GetId());
1043         break;
1044       case UIResourceRequest::UIResourceInvalidRequest:
1045         NOTREACHED();
1046         break;
1047     }
1048   }
1049
1050   // If all UI resource evictions were not recreated by processing this queue,
1051   // then another commit is required.
1052   if (layer_tree_host_impl_->EvictedUIResourcesExist())
1053     layer_tree_host_impl_->SetNeedsCommit();
1054 }
1055
1056 void LayerTreeImpl::AddLayerWithCopyOutputRequest(LayerImpl* layer) {
1057   // Only the active tree needs to know about layers with copy requests, as
1058   // they are aborted if not serviced during draw.
1059   DCHECK(IsActiveTree());
1060
1061   // DCHECK(std::find(layers_with_copy_output_request_.begin(),
1062   //                 layers_with_copy_output_request_.end(),
1063   //                 layer) == layers_with_copy_output_request_.end());
1064   // TODO(danakj): Remove this once crash is found crbug.com/309777
1065   for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1066     CHECK(layers_with_copy_output_request_[i] != layer)
1067         << i << " of " << layers_with_copy_output_request_.size();
1068   }
1069   layers_with_copy_output_request_.push_back(layer);
1070 }
1071
1072 void LayerTreeImpl::RemoveLayerWithCopyOutputRequest(LayerImpl* layer) {
1073   // Only the active tree needs to know about layers with copy requests, as
1074   // they are aborted if not serviced during draw.
1075   DCHECK(IsActiveTree());
1076
1077   std::vector<LayerImpl*>::iterator it = std::find(
1078       layers_with_copy_output_request_.begin(),
1079       layers_with_copy_output_request_.end(),
1080       layer);
1081   DCHECK(it != layers_with_copy_output_request_.end());
1082   layers_with_copy_output_request_.erase(it);
1083
1084   // TODO(danakj): Remove this once crash is found crbug.com/309777
1085   for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1086     CHECK(layers_with_copy_output_request_[i] != layer)
1087         << i << " of " << layers_with_copy_output_request_.size();
1088   }
1089 }
1090
1091 const std::vector<LayerImpl*>& LayerTreeImpl::LayersWithCopyOutputRequest()
1092     const {
1093   // Only the active tree needs to know about layers with copy requests, as
1094   // they are aborted if not serviced during draw.
1095   DCHECK(IsActiveTree());
1096
1097   return layers_with_copy_output_request_;
1098 }
1099
1100 void LayerTreeImpl::ReleaseResourcesRecursive(LayerImpl* current) {
1101   DCHECK(current);
1102   current->ReleaseResources();
1103   if (current->mask_layer())
1104     ReleaseResourcesRecursive(current->mask_layer());
1105   if (current->replica_layer())
1106     ReleaseResourcesRecursive(current->replica_layer());
1107   for (size_t i = 0; i < current->children().size(); ++i)
1108     ReleaseResourcesRecursive(current->children()[i]);
1109 }
1110
1111 template <typename LayerType>
1112 static inline bool LayerClipsSubtree(LayerType* layer) {
1113   return layer->masks_to_bounds() || layer->mask_layer();
1114 }
1115
1116 static bool PointHitsRect(
1117     const gfx::PointF& screen_space_point,
1118     const gfx::Transform& local_space_to_screen_space_transform,
1119     const gfx::RectF& local_space_rect,
1120     float* distance_to_camera) {
1121   // If the transform is not invertible, then assume that this point doesn't hit
1122   // this rect.
1123   gfx::Transform inverse_local_space_to_screen_space(
1124       gfx::Transform::kSkipInitialization);
1125   if (!local_space_to_screen_space_transform.GetInverse(
1126           &inverse_local_space_to_screen_space))
1127     return false;
1128
1129   // Transform the hit test point from screen space to the local space of the
1130   // given rect.
1131   bool clipped = false;
1132   gfx::Point3F planar_point = MathUtil::ProjectPoint3D(
1133       inverse_local_space_to_screen_space, screen_space_point, &clipped);
1134   gfx::PointF hit_test_point_in_local_space =
1135       gfx::PointF(planar_point.x(), planar_point.y());
1136
1137   // If ProjectPoint could not project to a valid value, then we assume that
1138   // this point doesn't hit this rect.
1139   if (clipped)
1140     return false;
1141
1142   if (!local_space_rect.Contains(hit_test_point_in_local_space))
1143     return false;
1144
1145   if (distance_to_camera) {
1146     // To compute the distance to the camera, we have to take the planar point
1147     // and pull it back to world space and compute the displacement along the
1148     // z-axis.
1149     gfx::Point3F planar_point_in_screen_space(planar_point);
1150     local_space_to_screen_space_transform.TransformPoint(
1151         &planar_point_in_screen_space);
1152     *distance_to_camera = planar_point_in_screen_space.z();
1153   }
1154
1155   return true;
1156 }
1157
1158 static bool PointHitsRegion(const gfx::PointF& screen_space_point,
1159                             const gfx::Transform& screen_space_transform,
1160                             const Region& layer_space_region,
1161                             float layer_content_scale_x,
1162                             float layer_content_scale_y) {
1163   // If the transform is not invertible, then assume that this point doesn't hit
1164   // this region.
1165   gfx::Transform inverse_screen_space_transform(
1166       gfx::Transform::kSkipInitialization);
1167   if (!screen_space_transform.GetInverse(&inverse_screen_space_transform))
1168     return false;
1169
1170   // Transform the hit test point from screen space to the local space of the
1171   // given region.
1172   bool clipped = false;
1173   gfx::PointF hit_test_point_in_content_space = MathUtil::ProjectPoint(
1174       inverse_screen_space_transform, screen_space_point, &clipped);
1175   gfx::PointF hit_test_point_in_layer_space =
1176       gfx::ScalePoint(hit_test_point_in_content_space,
1177                       1.f / layer_content_scale_x,
1178                       1.f / layer_content_scale_y);
1179
1180   // If ProjectPoint could not project to a valid value, then we assume that
1181   // this point doesn't hit this region.
1182   if (clipped)
1183     return false;
1184
1185   return layer_space_region.Contains(
1186       gfx::ToRoundedPoint(hit_test_point_in_layer_space));
1187 }
1188
1189 static const LayerImpl* GetNextClippingLayer(const LayerImpl* layer) {
1190   if (layer->scroll_parent())
1191     return layer->scroll_parent();
1192   if (layer->clip_parent())
1193     return layer->clip_parent();
1194   return layer->parent();
1195 }
1196
1197 static bool PointIsClippedBySurfaceOrClipRect(
1198     const gfx::PointF& screen_space_point,
1199     const LayerImpl* layer) {
1200   // Walk up the layer tree and hit-test any render_surfaces and any layer
1201   // clip rects that are active.
1202   for (; layer; layer = GetNextClippingLayer(layer)) {
1203     if (layer->render_surface() &&
1204         !PointHitsRect(screen_space_point,
1205                        layer->render_surface()->screen_space_transform(),
1206                        layer->render_surface()->content_rect(),
1207                        NULL))
1208       return true;
1209
1210     if (LayerClipsSubtree(layer) &&
1211         !PointHitsRect(screen_space_point,
1212                        layer->screen_space_transform(),
1213                        gfx::Rect(layer->content_bounds()),
1214                        NULL))
1215       return true;
1216   }
1217
1218   // If we have finished walking all ancestors without having already exited,
1219   // then the point is not clipped by any ancestors.
1220   return false;
1221 }
1222
1223 static bool PointHitsLayer(const LayerImpl* layer,
1224                            const gfx::PointF& screen_space_point,
1225                            float* distance_to_intersection) {
1226   gfx::RectF content_rect(layer->content_bounds());
1227   if (!PointHitsRect(screen_space_point,
1228                      layer->screen_space_transform(),
1229                      content_rect,
1230                      distance_to_intersection))
1231     return false;
1232
1233   // At this point, we think the point does hit the layer, but we need to walk
1234   // up the parents to ensure that the layer was not clipped in such a way
1235   // that the hit point actually should not hit the layer.
1236   if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer))
1237     return false;
1238
1239   // Skip the HUD layer.
1240   if (layer == layer->layer_tree_impl()->hud_layer())
1241     return false;
1242
1243   return true;
1244 }
1245
1246 struct FindClosestMatchingLayerDataForRecursion {
1247   FindClosestMatchingLayerDataForRecursion()
1248       : closest_match(NULL),
1249         closest_distance(-std::numeric_limits<float>::infinity()) {}
1250   LayerImpl* closest_match;
1251   // Note that the positive z-axis points towards the camera, so bigger means
1252   // closer in this case, counterintuitively.
1253   float closest_distance;
1254 };
1255
1256 template <typename Functor>
1257 static void FindClosestMatchingLayer(
1258     const gfx::PointF& screen_space_point,
1259     LayerImpl* layer,
1260     const Functor& func,
1261     FindClosestMatchingLayerDataForRecursion* data_for_recursion) {
1262   for (int i = layer->children().size() - 1; i >= 0; --i) {
1263     FindClosestMatchingLayer(
1264         screen_space_point, layer->children()[i], func, data_for_recursion);
1265   }
1266
1267   float distance_to_intersection = 0.f;
1268   if (func(layer) &&
1269       PointHitsLayer(layer, screen_space_point, &distance_to_intersection) &&
1270       ((!data_for_recursion->closest_match ||
1271         distance_to_intersection > data_for_recursion->closest_distance))) {
1272     data_for_recursion->closest_distance = distance_to_intersection;
1273     data_for_recursion->closest_match = layer;
1274   }
1275 }
1276
1277 static bool ScrollsAnyDrawnRenderSurfaceLayerListMember(LayerImpl* layer) {
1278   if (!layer->scrollable())
1279     return false;
1280   if (layer->IsDrawnRenderSurfaceLayerListMember())
1281     return true;
1282   if (!layer->scroll_children())
1283     return false;
1284   for (std::set<LayerImpl*>::const_iterator it =
1285            layer->scroll_children()->begin();
1286        it != layer->scroll_children()->end();
1287        ++it) {
1288     if ((*it)->IsDrawnRenderSurfaceLayerListMember())
1289       return true;
1290   }
1291   return false;
1292 }
1293
1294 struct FindScrollingLayerFunctor {
1295   bool operator()(LayerImpl* layer) const {
1296     return ScrollsAnyDrawnRenderSurfaceLayerListMember(layer);
1297   }
1298 };
1299
1300 LayerImpl* LayerTreeImpl::FindFirstScrollingLayerThatIsHitByPoint(
1301     const gfx::PointF& screen_space_point) {
1302   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1303   FindClosestMatchingLayer(screen_space_point,
1304                            root_layer(),
1305                            FindScrollingLayerFunctor(),
1306                            &data_for_recursion);
1307   return data_for_recursion.closest_match;
1308 }
1309
1310 struct HitTestVisibleScrollableOrTouchableFunctor {
1311   bool operator()(LayerImpl* layer) const {
1312     return layer->IsDrawnRenderSurfaceLayerListMember() ||
1313            ScrollsAnyDrawnRenderSurfaceLayerListMember(layer) ||
1314            !layer->touch_event_handler_region().IsEmpty() ||
1315            layer->have_wheel_event_handlers();
1316   }
1317 };
1318
1319 LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPoint(
1320     const gfx::PointF& screen_space_point) {
1321   if (!root_layer())
1322     return NULL;
1323   if (!UpdateDrawProperties())
1324     return NULL;
1325   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1326   FindClosestMatchingLayer(screen_space_point,
1327                            root_layer(),
1328                            HitTestVisibleScrollableOrTouchableFunctor(),
1329                            &data_for_recursion);
1330   return data_for_recursion.closest_match;
1331 }
1332
1333 static bool LayerHasTouchEventHandlersAt(const gfx::PointF& screen_space_point,
1334                                          LayerImpl* layer_impl) {
1335   if (layer_impl->touch_event_handler_region().IsEmpty())
1336     return false;
1337
1338   if (!PointHitsRegion(screen_space_point,
1339                        layer_impl->screen_space_transform(),
1340                        layer_impl->touch_event_handler_region(),
1341                        layer_impl->contents_scale_x(),
1342                        layer_impl->contents_scale_y()))
1343     return false;
1344
1345   // At this point, we think the point does hit the touch event handler region
1346   // on the layer, but we need to walk up the parents to ensure that the layer
1347   // was not clipped in such a way that the hit point actually should not hit
1348   // the layer.
1349   if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer_impl))
1350     return false;
1351
1352   return true;
1353 }
1354
1355 struct FindTouchEventLayerFunctor {
1356   bool operator()(LayerImpl* layer) const {
1357     return LayerHasTouchEventHandlersAt(screen_space_point, layer);
1358   }
1359   const gfx::PointF screen_space_point;
1360 };
1361
1362 LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPointInTouchHandlerRegion(
1363     const gfx::PointF& screen_space_point) {
1364   if (!root_layer())
1365     return NULL;
1366   if (!UpdateDrawProperties())
1367     return NULL;
1368   FindTouchEventLayerFunctor func = {screen_space_point};
1369   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1370   FindClosestMatchingLayer(
1371       screen_space_point, root_layer(), func, &data_for_recursion);
1372   return data_for_recursion.closest_match;
1373 }
1374
1375 void LayerTreeImpl::RegisterSelection(const LayerSelectionBound& start,
1376                                       const LayerSelectionBound& end) {
1377   selection_start_ = start;
1378   selection_end_ = end;
1379 }
1380
1381 static ViewportSelectionBound ComputeViewportSelection(
1382     const LayerSelectionBound& layer_bound,
1383     LayerImpl* layer,
1384     float device_scale_factor) {
1385   ViewportSelectionBound viewport_bound;
1386   viewport_bound.type = layer_bound.type;
1387
1388   if (!layer || layer_bound.type == SELECTION_BOUND_EMPTY)
1389     return viewport_bound;
1390
1391   gfx::PointF layer_scaled_top = gfx::ScalePoint(layer_bound.edge_top,
1392                                                  layer->contents_scale_x(),
1393                                                  layer->contents_scale_y());
1394   gfx::PointF layer_scaled_bottom = gfx::ScalePoint(layer_bound.edge_bottom,
1395                                                     layer->contents_scale_x(),
1396                                                     layer->contents_scale_y());
1397
1398   bool clipped = false;
1399   gfx::PointF screen_top = MathUtil::MapPoint(
1400       layer->screen_space_transform(), layer_scaled_top, &clipped);
1401   gfx::PointF screen_bottom = MathUtil::MapPoint(
1402       layer->screen_space_transform(), layer_scaled_bottom, &clipped);
1403
1404   const float inv_scale = 1.f / device_scale_factor;
1405   viewport_bound.edge_top = gfx::ScalePoint(screen_top, inv_scale);
1406   viewport_bound.edge_bottom = gfx::ScalePoint(screen_bottom, inv_scale);
1407
1408   // The bottom edge point is used for visibility testing as it is the logical
1409   // focal point for bound selection handles (this may change in the future).
1410   // Shifting the visibility point fractionally inward ensures that neighboring
1411   // or logically coincident layers aligned to integral DPI coordinates will not
1412   // spuriously occlude the bound.
1413   gfx::Vector2dF visibility_offset = layer_scaled_top - layer_scaled_bottom;
1414   visibility_offset.Scale(device_scale_factor / visibility_offset.Length());
1415   gfx::PointF visibility_point = layer_scaled_bottom + visibility_offset;
1416   if (visibility_point.x() <= 0)
1417     visibility_point.set_x(visibility_point.x() + device_scale_factor);
1418   visibility_point = MathUtil::MapPoint(
1419       layer->screen_space_transform(), visibility_point, &clipped);
1420
1421   float intersect_distance = 0.f;
1422   viewport_bound.visible =
1423       PointHitsLayer(layer, visibility_point, &intersect_distance);
1424
1425   return viewport_bound;
1426 }
1427
1428 void LayerTreeImpl::GetViewportSelection(ViewportSelectionBound* start,
1429                                          ViewportSelectionBound* end) {
1430   DCHECK(start);
1431   DCHECK(end);
1432
1433   *start = ComputeViewportSelection(
1434       selection_start_,
1435       selection_start_.layer_id ? LayerById(selection_start_.layer_id) : NULL,
1436       device_scale_factor());
1437   if (start->type == SELECTION_BOUND_CENTER ||
1438       start->type == SELECTION_BOUND_EMPTY) {
1439     *end = *start;
1440   } else {
1441     *end = ComputeViewportSelection(
1442         selection_end_,
1443         selection_end_.layer_id ? LayerById(selection_end_.layer_id) : NULL,
1444         device_scale_factor());
1445   }
1446 }
1447
1448 void LayerTreeImpl::RegisterPictureLayerImpl(PictureLayerImpl* layer) {
1449   layer_tree_host_impl_->RegisterPictureLayerImpl(layer);
1450 }
1451
1452 void LayerTreeImpl::UnregisterPictureLayerImpl(PictureLayerImpl* layer) {
1453   layer_tree_host_impl_->UnregisterPictureLayerImpl(layer);
1454 }
1455
1456 void LayerTreeImpl::InputScrollAnimationFinished() {
1457   layer_tree_host_impl_->ScrollEnd();
1458 }
1459
1460 BlockingTaskRunner* LayerTreeImpl::BlockingMainThreadTaskRunner() const {
1461   return proxy()->blocking_main_thread_task_runner();
1462 }
1463
1464 void LayerTreeImpl::SetPageScaleAnimation(
1465     const gfx::Vector2d& target_offset,
1466     bool anchor_point,
1467     float page_scale,
1468     base::TimeDelta duration) {
1469   if (!InnerViewportScrollLayer())
1470     return;
1471
1472   gfx::ScrollOffset scroll_total = TotalScrollOffset();
1473   gfx::SizeF scaled_scrollable_size = ScrollableSize();
1474   gfx::SizeF viewport_size = InnerViewportContainerLayer()->bounds();
1475
1476   // Easing constants experimentally determined.
1477   scoped_ptr<TimingFunction> timing_function =
1478       CubicBezierTimingFunction::Create(.8, 0, .3, .9);
1479
1480   // TODO(miletus) : Pass in ScrollOffset.
1481   page_scale_animation_ =
1482       PageScaleAnimation::Create(ScrollOffsetToVector2dF(scroll_total),
1483                                  total_page_scale_factor(),
1484                                  viewport_size,
1485                                  scaled_scrollable_size,
1486                                  timing_function.Pass());
1487
1488   if (anchor_point) {
1489     gfx::Vector2dF anchor(target_offset);
1490     page_scale_animation_->ZoomWithAnchor(anchor,
1491                                           page_scale,
1492                                           duration.InSecondsF());
1493   } else {
1494     gfx::Vector2dF scaled_target_offset = target_offset;
1495     page_scale_animation_->ZoomTo(scaled_target_offset,
1496                                   page_scale,
1497                                   duration.InSecondsF());
1498   }
1499 }
1500
1501 scoped_ptr<PageScaleAnimation> LayerTreeImpl::TakePageScaleAnimation() {
1502   return page_scale_animation_.Pass();
1503 }
1504
1505 }  // namespace cc