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 <algorithm>
   8 #include <limits>
   9 #include <set>
  10
  11 #include "base/auto_reset.h"
  12 #include "base/trace_event/trace_event.h"
  13 #include "base/trace_event/trace_event_argument.h"
  14 #include "cc/animation/keyframed_animation_curve.h"
  15 #include "cc/animation/scrollbar_animation_controller.h"
  16 #include "cc/animation/scrollbar_animation_controller_linear_fade.h"
  17 #include "cc/animation/scrollbar_animation_controller_thinning.h"
  18 #include "cc/base/math_util.h"
  19 #include "cc/base/synced_property.h"
  20 #include "cc/base/util.h"
  21 #include "cc/debug/devtools_instrumentation.h"
  22 #include "cc/debug/traced_value.h"
  23 #include "cc/input/layer_scroll_offset_delegate.h"
  24 #include "cc/input/page_scale_animation.h"
  25 #include "cc/layers/heads_up_display_layer_impl.h"
  26 #include "cc/layers/layer.h"
  27 #include "cc/layers/layer_iterator.h"
  28 #include "cc/layers/render_surface_impl.h"
  29 #include "cc/layers/scrollbar_layer_impl_base.h"
  30 #include "cc/resources/ui_resource_request.h"
  31 #include "cc/trees/layer_tree_host_common.h"
  32 #include "cc/trees/layer_tree_host_impl.h"
  33 #include "cc/trees/occlusion_tracker.h"
  34 #include "ui/gfx/geometry/point_conversions.h"
  35 #include "ui/gfx/geometry/size_conversions.h"
  36 #include "ui/gfx/geometry/vector2d_conversions.h"
  37
  38 namespace cc {
  39
  40 LayerTreeImpl::LayerTreeImpl(
  41     LayerTreeHostImpl* layer_tree_host_impl,
  42     scoped_refptr<SyncedProperty<ScaleGroup>> page_scale_factor,
  43     scoped_refptr<SyncedTopControls> top_controls_shown_ratio,
  44     scoped_refptr<SyncedElasticOverscroll> elastic_overscroll)
  45     : layer_tree_host_impl_(layer_tree_host_impl),
  46       source_frame_number_(-1),
  47       hud_layer_(0),
  48       currently_scrolling_layer_(NULL),
  49       root_layer_scroll_offset_delegate_(NULL),
  50       background_color_(0),
  51       has_transparent_background_(false),
  52       overscroll_elasticity_layer_(NULL),
  53       page_scale_layer_(NULL),
  54       inner_viewport_scroll_layer_(NULL),
  55       outer_viewport_scroll_layer_(NULL),
  56       page_scale_factor_(page_scale_factor),
  57       min_page_scale_factor_(0),
  58       max_page_scale_factor_(0),
  59       elastic_overscroll_(elastic_overscroll),
  60       scrolling_layer_id_from_previous_tree_(0),
  61       contents_textures_purged_(false),
  62       viewport_size_invalid_(false),
  63       needs_update_draw_properties_(true),
  64       needs_full_tree_sync_(true),
  65       next_activation_forces_redraw_(false),
  66       has_ever_been_drawn_(false),
  67       render_surface_layer_list_id_(0),
  68       top_controls_shrink_blink_size_(false),
  69       top_controls_height_(0),
  70       top_controls_shown_ratio_(top_controls_shown_ratio) {
  71 }
  72
  73 LayerTreeImpl::~LayerTreeImpl() {
  74   BreakSwapPromises(SwapPromise::SWAP_FAILS);
  75
  76   // Need to explicitly clear the tree prior to destroying this so that
  77   // the LayerTreeImpl pointer is still valid in the LayerImpl dtor.
  78   DCHECK(!root_layer_);
  79   DCHECK(layers_with_copy_output_request_.empty());
  80 }
  81
  82 void LayerTreeImpl::Shutdown() {
  83   root_layer_ = nullptr;
  84 }
  85
  86 void LayerTreeImpl::ReleaseResources() {
  87   if (root_layer_) {
  88     LayerTreeHostCommon::CallFunctionForSubtree(
  89         root_layer_.get(), [](LayerImpl* layer) { layer->ReleaseResources(); });
  90   }
  91 }
  92
  93 void LayerTreeImpl::RecreateResources() {
  94   if (root_layer_) {
  95     LayerTreeHostCommon::CallFunctionForSubtree(
  96         root_layer_.get(),
  97         [](LayerImpl* layer) { layer->RecreateResources(); });
  98   }
  99 }
 100
 101 void LayerTreeImpl::GatherFrameTimingRequestIds(
 102     std::vector<int64_t>* request_ids) {
 103   if (!root_layer_)
 104     return;
 105
 106   // TODO(vmpstr): Early out if there are no requests on any of the layers. For
 107   // that, we need to inform LayerTreeImpl whenever there are requests when we
 108   // get them.
 109   LayerTreeHostCommon::CallFunctionForSubtree(
 110       root_layer_.get(), [request_ids](LayerImpl* layer) {
 111         layer->GatherFrameTimingRequestIds(request_ids);
 112       });
 113 }
 114
 115 bool LayerTreeImpl::IsExternalFlingActive() const {
 116   return root_layer_scroll_offset_delegate_ &&
 117          root_layer_scroll_offset_delegate_->IsExternalFlingActive();
 118 }
 119
 120 void LayerTreeImpl::DidUpdateScrollOffset(int layer_id) {
 121   int inner_layer_id = InnerViewportScrollLayer()
 122                            ? InnerViewportScrollLayer()->id()
 123                            : Layer::INVALID_ID;
 124   int outer_layer_id = OuterViewportScrollLayer()
 125                            ? OuterViewportScrollLayer()->id()
 126                            : Layer::INVALID_ID;
 127   if (layer_id != outer_layer_id && layer_id != inner_layer_id)
 128     return;
 129
 130   if (!root_layer_scroll_offset_delegate_)
 131     return;
 132
 133   UpdateRootScrollOffsetDelegate();
 134 }
 135
 136 void LayerTreeImpl::SetRootLayer(scoped_ptr<LayerImpl> layer) {
 137   root_layer_ = layer.Pass();
 138   currently_scrolling_layer_ = NULL;
 139   inner_viewport_scroll_layer_ = NULL;
 140   outer_viewport_scroll_layer_ = NULL;
 141   page_scale_layer_ = NULL;
 142
 143   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 144 }
 145
 146 LayerImpl* LayerTreeImpl::InnerViewportScrollLayer() const {
 147   return inner_viewport_scroll_layer_;
 148 }
 149
 150 LayerImpl* LayerTreeImpl::OuterViewportScrollLayer() const {
 151   return outer_viewport_scroll_layer_;
 152 }
 153
 154 gfx::ScrollOffset LayerTreeImpl::TotalScrollOffset() const {
 155   gfx::ScrollOffset offset;
 156
 157   if (inner_viewport_scroll_layer_)
 158     offset += inner_viewport_scroll_layer_->CurrentScrollOffset();
 159
 160   if (outer_viewport_scroll_layer_)
 161     offset += outer_viewport_scroll_layer_->CurrentScrollOffset();
 162
 163   return offset;
 164 }
 165
 166 gfx::ScrollOffset LayerTreeImpl::TotalMaxScrollOffset() const {
 167   gfx::ScrollOffset offset;
 168
 169   if (inner_viewport_scroll_layer_)
 170     offset += inner_viewport_scroll_layer_->MaxScrollOffset();
 171
 172   if (outer_viewport_scroll_layer_)
 173     offset += outer_viewport_scroll_layer_->MaxScrollOffset();
 174
 175   return offset;
 176 }
 177
 178 scoped_ptr<LayerImpl> LayerTreeImpl::DetachLayerTree() {
 179   // Clear all data structures that have direct references to the layer tree.
 180   scrolling_layer_id_from_previous_tree_ =
 181     currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0;
 182   inner_viewport_scroll_layer_ = NULL;
 183   outer_viewport_scroll_layer_ = NULL;
 184   page_scale_layer_ = NULL;
 185   currently_scrolling_layer_ = NULL;
 186
 187   render_surface_layer_list_.clear();
 188   set_needs_update_draw_properties();
 189   return root_layer_.Pass();
 190 }
 191
 192 void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
 193   // The request queue should have been processed and does not require a push.
 194   DCHECK_EQ(ui_resource_request_queue_.size(), 0u);
 195
 196   if (next_activation_forces_redraw_) {
 197     target_tree->ForceRedrawNextActivation();
 198     next_activation_forces_redraw_ = false;
 199   }
 200
 201   target_tree->PassSwapPromises(&swap_promise_list_);
 202
 203   target_tree->set_top_controls_shrink_blink_size(
 204       top_controls_shrink_blink_size_);
 205   target_tree->set_top_controls_height(top_controls_height_);
 206   target_tree->PushTopControls(nullptr);
 207
 208   // Active tree already shares the page_scale_factor object with pending
 209   // tree so only the limits need to be provided.
 210   target_tree->PushPageScaleFactorAndLimits(nullptr, min_page_scale_factor(),
 211                                             max_page_scale_factor());
 212   target_tree->elastic_overscroll()->PushPendingToActive();
 213
 214   target_tree->pending_page_scale_animation_ =
 215       pending_page_scale_animation_.Pass();
 216
 217   if (page_scale_layer_ && inner_viewport_scroll_layer_) {
 218     target_tree->SetViewportLayersFromIds(
 219         overscroll_elasticity_layer_ ? overscroll_elasticity_layer_->id()
 220                                      : Layer::INVALID_ID,
 221         page_scale_layer_->id(), inner_viewport_scroll_layer_->id(),
 222         outer_viewport_scroll_layer_ ? outer_viewport_scroll_layer_->id()
 223                                      : Layer::INVALID_ID);
 224   } else {
 225     target_tree->ClearViewportLayers();
 226   }
 227
 228   target_tree->RegisterSelection(selection_start_, selection_end_);
 229
 230   // This should match the property synchronization in
 231   // LayerTreeHost::finishCommitOnImplThread().
 232   target_tree->set_source_frame_number(source_frame_number());
 233   target_tree->set_background_color(background_color());
 234   target_tree->set_has_transparent_background(has_transparent_background());
 235
 236   if (ContentsTexturesPurged())
 237     target_tree->SetContentsTexturesPurged();
 238   else
 239     target_tree->ResetContentsTexturesPurged();
 240
 241   if (ViewportSizeInvalid())
 242     target_tree->SetViewportSizeInvalid();
 243   else
 244     target_tree->ResetViewportSizeInvalid();
 245
 246   if (hud_layer())
 247     target_tree->set_hud_layer(static_cast<HeadsUpDisplayLayerImpl*>(
 248         LayerTreeHostCommon::FindLayerInSubtree(
 249             target_tree->root_layer(), hud_layer()->id())));
 250   else
 251     target_tree->set_hud_layer(NULL);
 252
 253   target_tree->has_ever_been_drawn_ = false;
 254 }
 255
 256 LayerImpl* LayerTreeImpl::InnerViewportContainerLayer() const {
 257   return inner_viewport_scroll_layer_
 258              ? inner_viewport_scroll_layer_->scroll_clip_layer()
 259              : NULL;
 260 }
 261
 262 LayerImpl* LayerTreeImpl::OuterViewportContainerLayer() const {
 263   return outer_viewport_scroll_layer_
 264              ? outer_viewport_scroll_layer_->scroll_clip_layer()
 265              : NULL;
 266 }
 267
 268 LayerImpl* LayerTreeImpl::CurrentlyScrollingLayer() const {
 269   DCHECK(IsActiveTree());
 270   return currently_scrolling_layer_;
 271 }
 272
 273 void LayerTreeImpl::SetCurrentlyScrollingLayer(LayerImpl* layer) {
 274   if (currently_scrolling_layer_ == layer)
 275     return;
 276
 277   if (currently_scrolling_layer_ &&
 278       currently_scrolling_layer_->scrollbar_animation_controller())
 279     currently_scrolling_layer_->scrollbar_animation_controller()
 280         ->DidScrollEnd();
 281   currently_scrolling_layer_ = layer;
 282   if (layer && layer->scrollbar_animation_controller())
 283     layer->scrollbar_animation_controller()->DidScrollBegin();
 284 }
 285
 286 void LayerTreeImpl::ClearCurrentlyScrollingLayer() {
 287   SetCurrentlyScrollingLayer(NULL);
 288   scrolling_layer_id_from_previous_tree_ = 0;
 289 }
 290
 291 namespace {
 292
 293 void ForceScrollbarParameterUpdateAfterScaleChange(LayerImpl* current_layer) {
 294   if (!current_layer)
 295     return;
 296
 297   while (current_layer) {
 298     current_layer->ScrollbarParametersDidChange(false);
 299     current_layer = current_layer->parent();
 300   }
 301 }
 302
 303 }  // namespace
 304
 305 float LayerTreeImpl::ClampPageScaleFactorToLimits(
 306     float page_scale_factor) const {
 307   if (min_page_scale_factor_ && page_scale_factor < min_page_scale_factor_)
 308     page_scale_factor = min_page_scale_factor_;
 309   else if (max_page_scale_factor_ && page_scale_factor > max_page_scale_factor_)
 310     page_scale_factor = max_page_scale_factor_;
 311   return page_scale_factor;
 312 }
 313
 314 void LayerTreeImpl::SetPageScaleOnActiveTree(float active_page_scale) {
 315   DCHECK(IsActiveTree());
 316   if (page_scale_factor()->SetCurrent(
 317           ClampPageScaleFactorToLimits(active_page_scale)))
 318     DidUpdatePageScale();
 319 }
 320
 321 void LayerTreeImpl::PushPageScaleFromMainThread(float page_scale_factor,
 322                                                 float min_page_scale_factor,
 323                                                 float max_page_scale_factor) {
 324   PushPageScaleFactorAndLimits(&page_scale_factor, min_page_scale_factor,
 325                                max_page_scale_factor);
 326 }
 327
 328 void LayerTreeImpl::PushPageScaleFactorAndLimits(const float* page_scale_factor,
 329                                                  float min_page_scale_factor,
 330                                                  float max_page_scale_factor) {
 331   DCHECK(page_scale_factor || IsActiveTree());
 332   bool changed_page_scale = false;
 333   if (page_scale_factor) {
 334     DCHECK(!IsActiveTree() || !layer_tree_host_impl_->pending_tree());
 335     changed_page_scale |=
 336         page_scale_factor_->PushFromMainThread(*page_scale_factor);
 337   }
 338   if (IsActiveTree())
 339     changed_page_scale |= page_scale_factor_->PushPendingToActive();
 340   changed_page_scale |=
 341       SetPageScaleFactorLimits(min_page_scale_factor, max_page_scale_factor);
 342
 343   if (changed_page_scale)
 344     DidUpdatePageScale();
 345 }
 346
 347 void LayerTreeImpl::set_top_controls_shrink_blink_size(bool shrink) {
 348   if (top_controls_shrink_blink_size_ == shrink)
 349     return;
 350
 351   top_controls_shrink_blink_size_ = shrink;
 352   if (IsActiveTree())
 353     layer_tree_host_impl_->UpdateViewportContainerSizes();
 354 }
 355
 356 void LayerTreeImpl::set_top_controls_height(float top_controls_height) {
 357   if (top_controls_height_ == top_controls_height)
 358     return;
 359
 360   top_controls_height_ = top_controls_height;
 361   if (IsActiveTree())
 362     layer_tree_host_impl_->UpdateViewportContainerSizes();
 363 }
 364
 365 bool LayerTreeImpl::SetCurrentTopControlsShownRatio(float ratio) {
 366   ratio = std::max(ratio, 0.f);
 367   ratio = std::min(ratio, 1.f);
 368   return top_controls_shown_ratio_->SetCurrent(ratio);
 369 }
 370
 371 void LayerTreeImpl::PushTopControlsFromMainThread(
 372     float top_controls_shown_ratio) {
 373   PushTopControls(&top_controls_shown_ratio);
 374 }
 375
 376 void LayerTreeImpl::PushTopControls(const float* top_controls_shown_ratio) {
 377   DCHECK(top_controls_shown_ratio || IsActiveTree());
 378
 379   if (top_controls_shown_ratio) {
 380     DCHECK(!IsActiveTree() || !layer_tree_host_impl_->pending_tree());
 381     top_controls_shown_ratio_->PushFromMainThread(*top_controls_shown_ratio);
 382   }
 383   if (IsActiveTree()) {
 384     if (top_controls_shown_ratio_->PushPendingToActive())
 385       layer_tree_host_impl_->DidChangeTopControlsPosition();
 386   }
 387 }
 388
 389 bool LayerTreeImpl::SetPageScaleFactorLimits(float min_page_scale_factor,
 390                                              float max_page_scale_factor) {
 391   if (min_page_scale_factor == min_page_scale_factor_ &&
 392       max_page_scale_factor == max_page_scale_factor_)
 393     return false;
 394
 395   min_page_scale_factor_ = min_page_scale_factor;
 396   max_page_scale_factor_ = max_page_scale_factor;
 397
 398   return true;
 399 }
 400
 401 void LayerTreeImpl::DidUpdatePageScale() {
 402   if (IsActiveTree())
 403     page_scale_factor()->SetCurrent(
 404         ClampPageScaleFactorToLimits(current_page_scale_factor()));
 405
 406   set_needs_update_draw_properties();
 407
 408   if (root_layer_scroll_offset_delegate_) {
 409     root_layer_scroll_offset_delegate_->UpdateRootLayerState(
 410         TotalScrollOffset(), TotalMaxScrollOffset(), ScrollableSize(),
 411         current_page_scale_factor(), min_page_scale_factor_,
 412         max_page_scale_factor_);
 413   }
 414
 415   ForceScrollbarParameterUpdateAfterScaleChange(page_scale_layer());
 416
 417   HideInnerViewportScrollbarsIfNearMinimumScale();
 418 }
 419
 420 void LayerTreeImpl::HideInnerViewportScrollbarsIfNearMinimumScale() {
 421   if (!InnerViewportContainerLayer())
 422     return;
 423
 424   LayerImpl::ScrollbarSet* scrollbars =
 425       InnerViewportContainerLayer()->scrollbars();
 426
 427   if (!scrollbars)
 428     return;
 429
 430   for (LayerImpl::ScrollbarSet::iterator it = scrollbars->begin();
 431        it != scrollbars->end();
 432        ++it) {
 433     ScrollbarLayerImplBase* scrollbar = *it;
 434     float minimum_scale_to_show_at =
 435         min_page_scale_factor() * settings().scrollbar_show_scale_threshold;
 436     scrollbar->SetHideLayerAndSubtree(
 437         current_page_scale_factor() < minimum_scale_to_show_at);
 438   }
 439 }
 440
 441 SyncedProperty<ScaleGroup>* LayerTreeImpl::page_scale_factor() {
 442   return page_scale_factor_.get();
 443 }
 444
 445 const SyncedProperty<ScaleGroup>* LayerTreeImpl::page_scale_factor() const {
 446   return page_scale_factor_.get();
 447 }
 448
 449 gfx::SizeF LayerTreeImpl::ScrollableViewportSize() const {
 450   if (!InnerViewportContainerLayer())
 451     return gfx::SizeF();
 452
 453   return gfx::ScaleSize(InnerViewportContainerLayer()->BoundsForScrolling(),
 454                         1.0f / current_page_scale_factor());
 455 }
 456
 457 gfx::Rect LayerTreeImpl::RootScrollLayerDeviceViewportBounds() const {
 458   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
 459                                      ? OuterViewportScrollLayer()
 460                                      : InnerViewportScrollLayer();
 461   if (!root_scroll_layer || root_scroll_layer->children().empty())
 462     return gfx::Rect();
 463   LayerImpl* layer = root_scroll_layer->children()[0];
 464   return MathUtil::MapEnclosingClippedRect(layer->screen_space_transform(),
 465                                            gfx::Rect(layer->content_bounds()));
 466 }
 467
 468 void LayerTreeImpl::ApplySentScrollAndScaleDeltasFromAbortedCommit() {
 469   DCHECK(IsActiveTree());
 470
 471   page_scale_factor()->AbortCommit();
 472   top_controls_shown_ratio()->AbortCommit();
 473   elastic_overscroll()->AbortCommit();
 474
 475   if (!root_layer())
 476     return;
 477
 478   LayerTreeHostCommon::CallFunctionForSubtree(
 479       root_layer(), [](LayerImpl* layer) {
 480         layer->ApplySentScrollDeltasFromAbortedCommit();
 481       });
 482 }
 483
 484 void LayerTreeImpl::SetViewportLayersFromIds(
 485     int overscroll_elasticity_layer_id,
 486     int page_scale_layer_id,
 487     int inner_viewport_scroll_layer_id,
 488     int outer_viewport_scroll_layer_id) {
 489   overscroll_elasticity_layer_ = LayerById(overscroll_elasticity_layer_id);
 490   page_scale_layer_ = LayerById(page_scale_layer_id);
 491   DCHECK(page_scale_layer_);
 492
 493   inner_viewport_scroll_layer_ =
 494       LayerById(inner_viewport_scroll_layer_id);
 495   DCHECK(inner_viewport_scroll_layer_);
 496
 497   outer_viewport_scroll_layer_ =
 498       LayerById(outer_viewport_scroll_layer_id);
 499   DCHECK(outer_viewport_scroll_layer_ ||
 500          outer_viewport_scroll_layer_id == Layer::INVALID_ID);
 501
 502   HideInnerViewportScrollbarsIfNearMinimumScale();
 503
 504   if (!root_layer_scroll_offset_delegate_)
 505     return;
 506 }
 507
 508 void LayerTreeImpl::ClearViewportLayers() {
 509   page_scale_layer_ = NULL;
 510   inner_viewport_scroll_layer_ = NULL;
 511   outer_viewport_scroll_layer_ = NULL;
 512 }
 513
 514 bool LayerTreeImpl::UpdateDrawProperties(bool update_lcd_text) {
 515   if (!needs_update_draw_properties_)
 516     return true;
 517
 518   // Calling UpdateDrawProperties must clear this flag, so there can be no
 519   // early outs before this.
 520   needs_update_draw_properties_ = false;
 521
 522   // For max_texture_size.  When the renderer is re-created in
 523   // CreateAndSetRenderer, the needs update draw properties flag is set
 524   // again.
 525   if (!layer_tree_host_impl_->renderer())
 526     return false;
 527
 528   // Clear this after the renderer early out, as it should still be
 529   // possible to hit test even without a renderer.
 530   render_surface_layer_list_.clear();
 531
 532   if (!root_layer())
 533     return false;
 534
 535   {
 536     TRACE_EVENT2(
 537         "cc", "LayerTreeImpl::UpdateDrawProperties::CalculateDrawProperties",
 538         "IsActive", IsActiveTree(), "SourceFrameNumber", source_frame_number_);
 539     LayerImpl* page_scale_layer =
 540         page_scale_layer_ ? page_scale_layer_ : InnerViewportContainerLayer();
 541     bool can_render_to_separate_surface =
 542         (layer_tree_host_impl_->GetDrawMode() !=
 543          DRAW_MODE_RESOURCELESS_SOFTWARE);
 544
 545     ++render_surface_layer_list_id_;
 546     LayerTreeHostCommon::CalcDrawPropsImplInputs inputs(
 547         root_layer(), DrawViewportSize(),
 548         layer_tree_host_impl_->DrawTransform(), device_scale_factor(),
 549         current_page_scale_factor(), page_scale_layer,
 550         elastic_overscroll()->Current(IsActiveTree()),
 551         overscroll_elasticity_layer_, resource_provider()->max_texture_size(),
 552         settings().can_use_lcd_text, settings().layers_always_allowed_lcd_text,
 553         can_render_to_separate_surface,
 554         settings().layer_transforms_should_scale_layer_contents,
 555         settings().verify_property_trees,
 556         &render_surface_layer_list_, render_surface_layer_list_id_);
 557     LayerTreeHostCommon::CalculateDrawProperties(&inputs);
 558   }
 559
 560   {
 561     TRACE_EVENT2("cc", "LayerTreeImpl::UpdateDrawProperties::Occlusion",
 562                  "IsActive", IsActiveTree(), "SourceFrameNumber",
 563                  source_frame_number_);
 564     OcclusionTracker<LayerImpl> occlusion_tracker(
 565         root_layer()->render_surface()->content_rect());
 566     occlusion_tracker.set_minimum_tracking_size(
 567         settings().minimum_occlusion_tracking_size);
 568
 569     // LayerIterator is used here instead of CallFunctionForSubtree to only
 570     // UpdateTilePriorities on layers that will be visible (and thus have valid
 571     // draw properties) and not because any ordering is required.
 572     auto end = LayerIterator<LayerImpl>::End(&render_surface_layer_list_);
 573     for (auto it = LayerIterator<LayerImpl>::Begin(&render_surface_layer_list_);
 574          it != end; ++it) {
 575       occlusion_tracker.EnterLayer(it);
 576
 577       // There are very few render targets so this should be cheap to do for
 578       // each layer instead of something more complicated.
 579       bool inside_replica = false;
 580       LayerImpl* layer = it->render_target();
 581       while (layer && !inside_replica) {
 582         if (layer->render_target()->has_replica())
 583           inside_replica = true;
 584         layer = layer->render_target()->parent();
 585       }
 586
 587       // Don't use occlusion if a layer will appear in a replica, since the
 588       // tile raster code does not know how to look for the replica and would
 589       // consider it occluded even though the replica is visible.
 590       // Since occlusion is only used for browser compositor (i.e.
 591       // use_occlusion_for_tile_prioritization) and it won't use replicas,
 592       // this should matter not.
 593
 594       if (it.represents_itself()) {
 595         Occlusion occlusion =
 596             inside_replica ? Occlusion()
 597                            : occlusion_tracker.GetCurrentOcclusionForLayer(
 598                                  it->draw_transform());
 599         it->draw_properties().occlusion_in_content_space = occlusion;
 600       }
 601
 602       if (it.represents_contributing_render_surface()) {
 603         // Surfaces aren't used by the tile raster code, so they can have
 604         // occlusion regardless of replicas.
 605         Occlusion occlusion =
 606             occlusion_tracker.GetCurrentOcclusionForContributingSurface(
 607                 it->render_surface()->draw_transform());
 608         it->render_surface()->set_occlusion_in_content_space(occlusion);
 609         // Masks are used to draw the contributing surface, so should have
 610         // the same occlusion as the surface (nothing inside the surface
 611         // occludes them).
 612         if (LayerImpl* mask = it->mask_layer()) {
 613           Occlusion mask_occlusion =
 614               inside_replica
 615                   ? Occlusion()
 616                   : occlusion_tracker.GetCurrentOcclusionForContributingSurface(
 617                         it->render_surface()->draw_transform() *
 618                         it->draw_transform());
 619           mask->draw_properties().occlusion_in_content_space = mask_occlusion;
 620         }
 621         if (LayerImpl* replica = it->replica_layer()) {
 622           if (LayerImpl* mask = replica->mask_layer())
 623             mask->draw_properties().occlusion_in_content_space = Occlusion();
 624         }
 625       }
 626
 627       occlusion_tracker.LeaveLayer(it);
 628     }
 629
 630     unoccluded_screen_space_region_ =
 631         occlusion_tracker.ComputeVisibleRegionInScreen();
 632   }
 633
 634   // It'd be ideal if this could be done earlier, but when the raster source
 635   // is updated from the main thread during push properties, update draw
 636   // properties has not occurred yet and so it's not clear whether or not the
 637   // layer can or cannot use lcd text.  So, this is the cleanup pass to
 638   // determine if the raster source needs to be replaced with a non-lcd
 639   // raster source due to draw properties.
 640   if (update_lcd_text) {
 641     // TODO(enne): Make LTHI::sync_tree return this value.
 642     LayerTreeImpl* sync_tree =
 643         layer_tree_host_impl_->proxy()->CommitToActiveTree()
 644             ? layer_tree_host_impl_->active_tree()
 645             : layer_tree_host_impl_->pending_tree();
 646     // If this is not the sync tree, then it is not safe to update lcd text
 647     // as it causes invalidations and the tiles may be in use.
 648     DCHECK_EQ(this, sync_tree);
 649     for (const auto& layer : picture_layers_)
 650       layer->UpdateCanUseLCDTextAfterCommit();
 651   }
 652
 653   {
 654     TRACE_EVENT_BEGIN2("cc", "LayerTreeImpl::UpdateDrawProperties::UpdateTiles",
 655                        "IsActive", IsActiveTree(), "SourceFrameNumber",
 656                        source_frame_number_);
 657     const bool resourceless_software_draw =
 658         (layer_tree_host_impl_->GetDrawMode() ==
 659          DRAW_MODE_RESOURCELESS_SOFTWARE);
 660     size_t layers_updated_count = 0;
 661     bool tile_priorities_updated = false;
 662     for (PictureLayerImpl* layer : picture_layers_) {
 663       if (!layer->IsDrawnRenderSurfaceLayerListMember())
 664         continue;
 665       ++layers_updated_count;
 666       tile_priorities_updated |= layer->UpdateTiles(resourceless_software_draw);
 667     }
 668
 669     if (tile_priorities_updated)
 670       DidModifyTilePriorities();
 671
 672     TRACE_EVENT_END1("cc", "LayerTreeImpl::UpdateTilePriorities",
 673                      "layers_updated_count", layers_updated_count);
 674   }
 675
 676   DCHECK(!needs_update_draw_properties_) <<
 677       "CalcDrawProperties should not set_needs_update_draw_properties()";
 678   return true;
 679 }
 680
 681 const LayerImplList& LayerTreeImpl::RenderSurfaceLayerList() const {
 682   // If this assert triggers, then the list is dirty.
 683   DCHECK(!needs_update_draw_properties_);
 684   return render_surface_layer_list_;
 685 }
 686
 687 const Region& LayerTreeImpl::UnoccludedScreenSpaceRegion() const {
 688   // If this assert triggers, then the render_surface_layer_list_ is dirty, so
 689   // the unoccluded_screen_space_region_ is not valid anymore.
 690   DCHECK(!needs_update_draw_properties_);
 691   return unoccluded_screen_space_region_;
 692 }
 693
 694 gfx::Size LayerTreeImpl::ScrollableSize() const {
 695   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
 696                                      ? OuterViewportScrollLayer()
 697                                      : InnerViewportScrollLayer();
 698   if (!root_scroll_layer || root_scroll_layer->children().empty())
 699     return gfx::Size();
 700   return root_scroll_layer->children()[0]->bounds();
 701 }
 702
 703 LayerImpl* LayerTreeImpl::LayerById(int id) {
 704   LayerIdMap::iterator iter = layer_id_map_.find(id);
 705   return iter != layer_id_map_.end() ? iter->second : NULL;
 706 }
 707
 708 void LayerTreeImpl::RegisterLayer(LayerImpl* layer) {
 709   DCHECK(!LayerById(layer->id()));
 710   layer_id_map_[layer->id()] = layer;
 711 }
 712
 713 void LayerTreeImpl::UnregisterLayer(LayerImpl* layer) {
 714   DCHECK(LayerById(layer->id()));
 715   layer_id_map_.erase(layer->id());
 716 }
 717
 718 size_t LayerTreeImpl::NumLayers() {
 719   return layer_id_map_.size();
 720 }
 721
 722 void LayerTreeImpl::PushPersistedState(LayerTreeImpl* pending_tree) {
 723   pending_tree->SetCurrentlyScrollingLayer(
 724       LayerTreeHostCommon::FindLayerInSubtree(pending_tree->root_layer(),
 725           currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0));
 726 }
 727
 728 void LayerTreeImpl::DidBecomeActive() {
 729   if (next_activation_forces_redraw_) {
 730     layer_tree_host_impl_->SetFullRootLayerDamage();
 731     next_activation_forces_redraw_ = false;
 732   }
 733
 734   if (scrolling_layer_id_from_previous_tree_) {
 735     currently_scrolling_layer_ = LayerTreeHostCommon::FindLayerInSubtree(
 736         root_layer(), scrolling_layer_id_from_previous_tree_);
 737   }
 738
 739   // Always reset this flag on activation, as we would only have activated
 740   // if we were in a good state.
 741   layer_tree_host_impl_->ResetRequiresHighResToDraw();
 742
 743   if (root_layer()) {
 744     LayerTreeHostCommon::CallFunctionForSubtree(
 745         root_layer(), [](LayerImpl* layer) { layer->DidBecomeActive(); });
 746   }
 747
 748   devtools_instrumentation::DidActivateLayerTree(layer_tree_host_impl_->id(),
 749                                                  source_frame_number_);
 750 }
 751
 752 bool LayerTreeImpl::ContentsTexturesPurged() const {
 753   return contents_textures_purged_;
 754 }
 755
 756 void LayerTreeImpl::SetContentsTexturesPurged() {
 757   if (contents_textures_purged_)
 758     return;
 759   contents_textures_purged_ = true;
 760   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 761 }
 762
 763 void LayerTreeImpl::ResetContentsTexturesPurged() {
 764   if (!contents_textures_purged_)
 765     return;
 766   contents_textures_purged_ = false;
 767   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 768 }
 769
 770 bool LayerTreeImpl::RequiresHighResToDraw() const {
 771   return layer_tree_host_impl_->RequiresHighResToDraw();
 772 }
 773
 774 bool LayerTreeImpl::ViewportSizeInvalid() const {
 775   return viewport_size_invalid_;
 776 }
 777
 778 void LayerTreeImpl::SetViewportSizeInvalid() {
 779   viewport_size_invalid_ = true;
 780   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 781 }
 782
 783 void LayerTreeImpl::ResetViewportSizeInvalid() {
 784   viewport_size_invalid_ = false;
 785   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 786 }
 787
 788 Proxy* LayerTreeImpl::proxy() const {
 789   return layer_tree_host_impl_->proxy();
 790 }
 791
 792 const LayerTreeSettings& LayerTreeImpl::settings() const {
 793   return layer_tree_host_impl_->settings();
 794 }
 795
 796 const LayerTreeDebugState& LayerTreeImpl::debug_state() const {
 797   return layer_tree_host_impl_->debug_state();
 798 }
 799
 800 const RendererCapabilitiesImpl& LayerTreeImpl::GetRendererCapabilities() const {
 801   return layer_tree_host_impl_->GetRendererCapabilities();
 802 }
 803
 804 ContextProvider* LayerTreeImpl::context_provider() const {
 805   return output_surface()->context_provider();
 806 }
 807
 808 OutputSurface* LayerTreeImpl::output_surface() const {
 809   return layer_tree_host_impl_->output_surface();
 810 }
 811
 812 ResourceProvider* LayerTreeImpl::resource_provider() const {
 813   return layer_tree_host_impl_->resource_provider();
 814 }
 815
 816 TileManager* LayerTreeImpl::tile_manager() const {
 817   return layer_tree_host_impl_->tile_manager();
 818 }
 819
 820 FrameRateCounter* LayerTreeImpl::frame_rate_counter() const {
 821   return layer_tree_host_impl_->fps_counter();
 822 }
 823
 824 PaintTimeCounter* LayerTreeImpl::paint_time_counter() const {
 825   return layer_tree_host_impl_->paint_time_counter();
 826 }
 827
 828 MemoryHistory* LayerTreeImpl::memory_history() const {
 829   return layer_tree_host_impl_->memory_history();
 830 }
 831
 832 gfx::Size LayerTreeImpl::device_viewport_size() const {
 833   return layer_tree_host_impl_->device_viewport_size();
 834 }
 835
 836 float LayerTreeImpl::device_scale_factor() const {
 837   return layer_tree_host_impl_->device_scale_factor();
 838 }
 839
 840 DebugRectHistory* LayerTreeImpl::debug_rect_history() const {
 841   return layer_tree_host_impl_->debug_rect_history();
 842 }
 843
 844 bool LayerTreeImpl::IsActiveTree() const {
 845   return layer_tree_host_impl_->active_tree() == this;
 846 }
 847
 848 bool LayerTreeImpl::IsPendingTree() const {
 849   return layer_tree_host_impl_->pending_tree() == this;
 850 }
 851
 852 bool LayerTreeImpl::IsRecycleTree() const {
 853   return layer_tree_host_impl_->recycle_tree() == this;
 854 }
 855
 856 bool LayerTreeImpl::IsSyncTree() const {
 857   return layer_tree_host_impl_->sync_tree() == this;
 858 }
 859
 860 LayerImpl* LayerTreeImpl::FindActiveTreeLayerById(int id) {
 861   LayerTreeImpl* tree = layer_tree_host_impl_->active_tree();
 862   if (!tree)
 863     return NULL;
 864   return tree->LayerById(id);
 865 }
 866
 867 LayerImpl* LayerTreeImpl::FindPendingTreeLayerById(int id) {
 868   LayerTreeImpl* tree = layer_tree_host_impl_->pending_tree();
 869   if (!tree)
 870     return NULL;
 871   return tree->LayerById(id);
 872 }
 873
 874 bool LayerTreeImpl::PinchGestureActive() const {
 875   return layer_tree_host_impl_->pinch_gesture_active();
 876 }
 877
 878 BeginFrameArgs LayerTreeImpl::CurrentBeginFrameArgs() const {
 879   return layer_tree_host_impl_->CurrentBeginFrameArgs();
 880 }
 881
 882 base::TimeDelta LayerTreeImpl::begin_impl_frame_interval() const {
 883   return layer_tree_host_impl_->begin_impl_frame_interval();
 884 }
 885
 886 void LayerTreeImpl::SetNeedsCommit() {
 887   layer_tree_host_impl_->SetNeedsCommit();
 888 }
 889
 890 gfx::Rect LayerTreeImpl::DeviceViewport() const {
 891   return layer_tree_host_impl_->DeviceViewport();
 892 }
 893
 894 gfx::Size LayerTreeImpl::DrawViewportSize() const {
 895   return layer_tree_host_impl_->DrawViewportSize();
 896 }
 897
 898 const gfx::Rect LayerTreeImpl::ViewportRectForTilePriority() const {
 899   return layer_tree_host_impl_->ViewportRectForTilePriority();
 900 }
 901
 902 scoped_ptr<ScrollbarAnimationController>
 903 LayerTreeImpl::CreateScrollbarAnimationController(LayerImpl* scrolling_layer) {
 904   DCHECK(settings().scrollbar_fade_delay_ms);
 905   DCHECK(settings().scrollbar_fade_duration_ms);
 906   base::TimeDelta delay =
 907       base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_delay_ms);
 908   base::TimeDelta resize_delay = base::TimeDelta::FromMilliseconds(
 909       settings().scrollbar_fade_resize_delay_ms);
 910   base::TimeDelta duration =
 911       base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_duration_ms);
 912   switch (settings().scrollbar_animator) {
 913     case LayerTreeSettings::LINEAR_FADE: {
 914       return ScrollbarAnimationControllerLinearFade::Create(
 915           scrolling_layer,
 916           layer_tree_host_impl_,
 917           delay,
 918           resize_delay,
 919           duration);
 920     }
 921     case LayerTreeSettings::THINNING: {
 922       return ScrollbarAnimationControllerThinning::Create(scrolling_layer,
 923                                                           layer_tree_host_impl_,
 924                                                           delay,
 925                                                           resize_delay,
 926                                                           duration);
 927     }
 928     case LayerTreeSettings::NO_ANIMATOR:
 929       NOTREACHED();
 930       break;
 931   }
 932   return nullptr;
 933 }
 934
 935 void LayerTreeImpl::DidAnimateScrollOffset() {
 936   layer_tree_host_impl_->DidAnimateScrollOffset();
 937 }
 938
 939 bool LayerTreeImpl::use_gpu_rasterization() const {
 940   return layer_tree_host_impl_->use_gpu_rasterization();
 941 }
 942
 943 GpuRasterizationStatus LayerTreeImpl::GetGpuRasterizationStatus() const {
 944   return layer_tree_host_impl_->gpu_rasterization_status();
 945 }
 946
 947 bool LayerTreeImpl::create_low_res_tiling() const {
 948   return layer_tree_host_impl_->create_low_res_tiling();
 949 }
 950
 951 void LayerTreeImpl::SetNeedsRedraw() {
 952   layer_tree_host_impl_->SetNeedsRedraw();
 953 }
 954
 955 AnimationRegistrar* LayerTreeImpl::GetAnimationRegistrar() const {
 956   return layer_tree_host_impl_->animation_registrar();
 957 }
 958
 959 void LayerTreeImpl::GetAllTilesAndPrioritiesForTracing(
 960     std::map<const Tile*, TilePriority>* tile_map) const {
 961   typedef LayerIterator<LayerImpl> LayerIteratorType;
 962   LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
 963   for (LayerIteratorType it =
 964            LayerIteratorType::Begin(&render_surface_layer_list_);
 965        it != end;
 966        ++it) {
 967     if (!it.represents_itself())
 968       continue;
 969     LayerImpl* layer_impl = *it;
 970     layer_impl->GetAllTilesAndPrioritiesForTracing(tile_map);
 971   }
 972 }
 973
 974 void LayerTreeImpl::AsValueInto(base::trace_event::TracedValue* state) const {
 975   TracedValue::MakeDictIntoImplicitSnapshot(state, "cc::LayerTreeImpl", this);
 976   state->SetInteger("source_frame_number", source_frame_number_);
 977
 978   state->BeginDictionary("root_layer");
 979   root_layer_->AsValueInto(state);
 980   state->EndDictionary();
 981
 982   state->BeginArray("render_surface_layer_list");
 983   typedef LayerIterator<LayerImpl> LayerIteratorType;
 984   LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
 985   for (LayerIteratorType it = LayerIteratorType::Begin(
 986            &render_surface_layer_list_); it != end; ++it) {
 987     if (!it.represents_itself())
 988       continue;
 989     TracedValue::AppendIDRef(*it, state);
 990   }
 991   state->EndArray();
 992
 993   state->BeginArray("swap_promise_trace_ids");
 994   for (size_t i = 0; i < swap_promise_list_.size(); i++)
 995     state->AppendDouble(swap_promise_list_[i]->TraceId());
 996   state->EndArray();
 997 }
 998
 999 void LayerTreeImpl::SetRootLayerScrollOffsetDelegate(
1000     LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate) {
1001   if (root_layer_scroll_offset_delegate_ == root_layer_scroll_offset_delegate)
1002     return;
1003
1004   root_layer_scroll_offset_delegate_ = root_layer_scroll_offset_delegate;
1005
1006   if (root_layer_scroll_offset_delegate_) {
1007     root_layer_scroll_offset_delegate_->UpdateRootLayerState(
1008         TotalScrollOffset(), TotalMaxScrollOffset(), ScrollableSize(),
1009         current_page_scale_factor(), min_page_scale_factor(),
1010         max_page_scale_factor());
1011
1012     DistributeRootScrollOffset();
1013   }
1014 }
1015
1016 void LayerTreeImpl::UpdateRootScrollOffsetDelegate() {
1017   DCHECK(root_layer_scroll_offset_delegate_);
1018
1019   gfx::ScrollOffset offset = InnerViewportScrollLayer()->CurrentScrollOffset();
1020
1021   if (OuterViewportScrollLayer())
1022     offset += OuterViewportScrollLayer()->CurrentScrollOffset();
1023
1024   root_layer_scroll_offset_delegate_->UpdateRootLayerState(
1025       offset, TotalMaxScrollOffset(), ScrollableSize(),
1026       current_page_scale_factor(), min_page_scale_factor(),
1027       max_page_scale_factor());
1028 }
1029
1030 void LayerTreeImpl::DistributeRootScrollOffset() {
1031   if (!root_layer_scroll_offset_delegate_)
1032     return;
1033
1034   gfx::ScrollOffset root_offset =
1035       root_layer_scroll_offset_delegate_->GetTotalScrollOffset();
1036
1037   if (!InnerViewportScrollLayer())
1038     return;
1039
1040   DCHECK(OuterViewportScrollLayer());
1041
1042   // If we get here, we have both inner/outer viewports, and need to distribute
1043   // the scroll offset between them.
1044   gfx::ScrollOffset inner_viewport_offset =
1045       InnerViewportScrollLayer()->CurrentScrollOffset();
1046   gfx::ScrollOffset outer_viewport_offset =
1047       OuterViewportScrollLayer()->CurrentScrollOffset();
1048
1049   // It may be nothing has changed.
1050   if (inner_viewport_offset + outer_viewport_offset == root_offset)
1051     return;
1052
1053   gfx::ScrollOffset max_outer_viewport_scroll_offset =
1054       OuterViewportScrollLayer()->MaxScrollOffset();
1055
1056   outer_viewport_offset = root_offset - inner_viewport_offset;
1057   outer_viewport_offset.SetToMin(max_outer_viewport_scroll_offset);
1058   outer_viewport_offset.SetToMax(gfx::ScrollOffset());
1059
1060   OuterViewportScrollLayer()->SetCurrentScrollOffsetFromDelegate(
1061       outer_viewport_offset);
1062   inner_viewport_offset = root_offset - outer_viewport_offset;
1063   InnerViewportScrollLayer()->SetCurrentScrollOffsetFromDelegate(
1064       inner_viewport_offset);
1065
1066   UpdateRootScrollOffsetDelegate();
1067 }
1068
1069 void LayerTreeImpl::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {
1070   DCHECK(swap_promise);
1071   swap_promise_list_.push_back(swap_promise.Pass());
1072 }
1073
1074 void LayerTreeImpl::PassSwapPromises(
1075     ScopedPtrVector<SwapPromise>* new_swap_promise) {
1076   swap_promise_list_.insert_and_take(swap_promise_list_.end(),
1077                                      new_swap_promise);
1078   new_swap_promise->clear();
1079 }
1080
1081 void LayerTreeImpl::FinishSwapPromises(CompositorFrameMetadata* metadata) {
1082   for (size_t i = 0; i < swap_promise_list_.size(); i++)
1083     swap_promise_list_[i]->DidSwap(metadata);
1084   swap_promise_list_.clear();
1085 }
1086
1087 void LayerTreeImpl::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
1088   for (size_t i = 0; i < swap_promise_list_.size(); i++)
1089     swap_promise_list_[i]->DidNotSwap(reason);
1090   swap_promise_list_.clear();
1091 }
1092
1093 void LayerTreeImpl::DidModifyTilePriorities() {
1094   layer_tree_host_impl_->DidModifyTilePriorities();
1095 }
1096
1097 void LayerTreeImpl::set_ui_resource_request_queue(
1098     const UIResourceRequestQueue& queue) {
1099   ui_resource_request_queue_ = queue;
1100 }
1101
1102 ResourceProvider::ResourceId LayerTreeImpl::ResourceIdForUIResource(
1103     UIResourceId uid) const {
1104   return layer_tree_host_impl_->ResourceIdForUIResource(uid);
1105 }
1106
1107 bool LayerTreeImpl::IsUIResourceOpaque(UIResourceId uid) const {
1108   return layer_tree_host_impl_->IsUIResourceOpaque(uid);
1109 }
1110
1111 void LayerTreeImpl::ProcessUIResourceRequestQueue() {
1112   for (const auto& req : ui_resource_request_queue_) {
1113     switch (req.GetType()) {
1114       case UIResourceRequest::UI_RESOURCE_CREATE:
1115         layer_tree_host_impl_->CreateUIResource(req.GetId(), req.GetBitmap());
1116         break;
1117       case UIResourceRequest::UI_RESOURCE_DELETE:
1118         layer_tree_host_impl_->DeleteUIResource(req.GetId());
1119         break;
1120       case UIResourceRequest::UI_RESOURCE_INVALID_REQUEST:
1121         NOTREACHED();
1122         break;
1123     }
1124   }
1125   ui_resource_request_queue_.clear();
1126
1127   // If all UI resource evictions were not recreated by processing this queue,
1128   // then another commit is required.
1129   if (layer_tree_host_impl_->EvictedUIResourcesExist())
1130     layer_tree_host_impl_->SetNeedsCommit();
1131 }
1132
1133 void LayerTreeImpl::RegisterPictureLayerImpl(PictureLayerImpl* layer) {
1134   DCHECK(std::find(picture_layers_.begin(), picture_layers_.end(), layer) ==
1135          picture_layers_.end());
1136   picture_layers_.push_back(layer);
1137 }
1138
1139 void LayerTreeImpl::UnregisterPictureLayerImpl(PictureLayerImpl* layer) {
1140   std::vector<PictureLayerImpl*>::iterator it =
1141       std::find(picture_layers_.begin(), picture_layers_.end(), layer);
1142   DCHECK(it != picture_layers_.end());
1143   picture_layers_.erase(it);
1144 }
1145
1146 void LayerTreeImpl::AddLayerWithCopyOutputRequest(LayerImpl* layer) {
1147   // Only the active tree needs to know about layers with copy requests, as
1148   // they are aborted if not serviced during draw.
1149   DCHECK(IsActiveTree());
1150
1151   // DCHECK(std::find(layers_with_copy_output_request_.begin(),
1152   //                 layers_with_copy_output_request_.end(),
1153   //                 layer) == layers_with_copy_output_request_.end());
1154   // TODO(danakj): Remove this once crash is found crbug.com/309777
1155   for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1156     CHECK(layers_with_copy_output_request_[i] != layer)
1157         << i << " of " << layers_with_copy_output_request_.size();
1158   }
1159   layers_with_copy_output_request_.push_back(layer);
1160 }
1161
1162 void LayerTreeImpl::RemoveLayerWithCopyOutputRequest(LayerImpl* layer) {
1163   // Only the active tree needs to know about layers with copy requests, as
1164   // they are aborted if not serviced during draw.
1165   DCHECK(IsActiveTree());
1166
1167   std::vector<LayerImpl*>::iterator it = std::find(
1168       layers_with_copy_output_request_.begin(),
1169       layers_with_copy_output_request_.end(),
1170       layer);
1171   DCHECK(it != layers_with_copy_output_request_.end());
1172   layers_with_copy_output_request_.erase(it);
1173
1174   // TODO(danakj): Remove this once crash is found crbug.com/309777
1175   for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1176     CHECK(layers_with_copy_output_request_[i] != layer)
1177         << i << " of " << layers_with_copy_output_request_.size();
1178   }
1179 }
1180
1181 const std::vector<LayerImpl*>& LayerTreeImpl::LayersWithCopyOutputRequest()
1182     const {
1183   // Only the active tree needs to know about layers with copy requests, as
1184   // they are aborted if not serviced during draw.
1185   DCHECK(IsActiveTree());
1186
1187   return layers_with_copy_output_request_;
1188 }
1189
1190 template <typename LayerType>
1191 static inline bool LayerClipsSubtree(LayerType* layer) {
1192   return layer->masks_to_bounds() || layer->mask_layer();
1193 }
1194
1195 static bool PointHitsRect(
1196     const gfx::PointF& screen_space_point,
1197     const gfx::Transform& local_space_to_screen_space_transform,
1198     const gfx::RectF& local_space_rect,
1199     float* distance_to_camera) {
1200   // If the transform is not invertible, then assume that this point doesn't hit
1201   // this rect.
1202   gfx::Transform inverse_local_space_to_screen_space(
1203       gfx::Transform::kSkipInitialization);
1204   if (!local_space_to_screen_space_transform.GetInverse(
1205           &inverse_local_space_to_screen_space))
1206     return false;
1207
1208   // Transform the hit test point from screen space to the local space of the
1209   // given rect.
1210   bool clipped = false;
1211   gfx::Point3F planar_point = MathUtil::ProjectPoint3D(
1212       inverse_local_space_to_screen_space, screen_space_point, &clipped);
1213   gfx::PointF hit_test_point_in_local_space =
1214       gfx::PointF(planar_point.x(), planar_point.y());
1215
1216   // If ProjectPoint could not project to a valid value, then we assume that
1217   // this point doesn't hit this rect.
1218   if (clipped)
1219     return false;
1220
1221   if (!local_space_rect.Contains(hit_test_point_in_local_space))
1222     return false;
1223
1224   if (distance_to_camera) {
1225     // To compute the distance to the camera, we have to take the planar point
1226     // and pull it back to world space and compute the displacement along the
1227     // z-axis.
1228     gfx::Point3F planar_point_in_screen_space(planar_point);
1229     local_space_to_screen_space_transform.TransformPoint(
1230         &planar_point_in_screen_space);
1231     *distance_to_camera = planar_point_in_screen_space.z();
1232   }
1233
1234   return true;
1235 }
1236
1237 static bool PointHitsRegion(const gfx::PointF& screen_space_point,
1238                             const gfx::Transform& screen_space_transform,
1239                             const Region& layer_space_region,
1240                             float layer_content_scale_x,
1241                             float layer_content_scale_y) {
1242   // If the transform is not invertible, then assume that this point doesn't hit
1243   // this region.
1244   gfx::Transform inverse_screen_space_transform(
1245       gfx::Transform::kSkipInitialization);
1246   if (!screen_space_transform.GetInverse(&inverse_screen_space_transform))
1247     return false;
1248
1249   // Transform the hit test point from screen space to the local space of the
1250   // given region.
1251   bool clipped = false;
1252   gfx::PointF hit_test_point_in_content_space = MathUtil::ProjectPoint(
1253       inverse_screen_space_transform, screen_space_point, &clipped);
1254   gfx::PointF hit_test_point_in_layer_space =
1255       gfx::ScalePoint(hit_test_point_in_content_space,
1256                       1.f / layer_content_scale_x,
1257                       1.f / layer_content_scale_y);
1258
1259   // If ProjectPoint could not project to a valid value, then we assume that
1260   // this point doesn't hit this region.
1261   if (clipped)
1262     return false;
1263
1264   return layer_space_region.Contains(
1265       gfx::ToRoundedPoint(hit_test_point_in_layer_space));
1266 }
1267
1268 static const LayerImpl* GetNextClippingLayer(const LayerImpl* layer) {
1269   if (layer->scroll_parent())
1270     return layer->scroll_parent();
1271   if (layer->clip_parent())
1272     return layer->clip_parent();
1273   return layer->parent();
1274 }
1275
1276 static bool PointIsClippedBySurfaceOrClipRect(
1277     const gfx::PointF& screen_space_point,
1278     const LayerImpl* layer) {
1279   // Walk up the layer tree and hit-test any render_surfaces and any layer
1280   // clip rects that are active.
1281   for (; layer; layer = GetNextClippingLayer(layer)) {
1282     if (layer->render_surface() &&
1283         !PointHitsRect(screen_space_point,
1284                        layer->render_surface()->screen_space_transform(),
1285                        layer->render_surface()->content_rect(),
1286                        NULL))
1287       return true;
1288
1289     if (LayerClipsSubtree(layer) &&
1290         !PointHitsRect(screen_space_point,
1291                        layer->screen_space_transform(),
1292                        gfx::Rect(layer->content_bounds()),
1293                        NULL))
1294       return true;
1295   }
1296
1297   // If we have finished walking all ancestors without having already exited,
1298   // then the point is not clipped by any ancestors.
1299   return false;
1300 }
1301
1302 static bool PointHitsLayer(const LayerImpl* layer,
1303                            const gfx::PointF& screen_space_point,
1304                            float* distance_to_intersection) {
1305   gfx::RectF content_rect(layer->content_bounds());
1306   if (!PointHitsRect(screen_space_point,
1307                      layer->screen_space_transform(),
1308                      content_rect,
1309                      distance_to_intersection))
1310     return false;
1311
1312   // At this point, we think the point does hit the layer, but we need to walk
1313   // up the parents to ensure that the layer was not clipped in such a way
1314   // that the hit point actually should not hit the layer.
1315   if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer))
1316     return false;
1317
1318   // Skip the HUD layer.
1319   if (layer == layer->layer_tree_impl()->hud_layer())
1320     return false;
1321
1322   return true;
1323 }
1324
1325 struct FindClosestMatchingLayerDataForRecursion {
1326   FindClosestMatchingLayerDataForRecursion()
1327       : closest_match(NULL),
1328         closest_distance(-std::numeric_limits<float>::infinity()) {}
1329   LayerImpl* closest_match;
1330   // Note that the positive z-axis points towards the camera, so bigger means
1331   // closer in this case, counterintuitively.
1332   float closest_distance;
1333 };
1334
1335 template <typename Functor>
1336 static void FindClosestMatchingLayer(
1337     const gfx::PointF& screen_space_point,
1338     LayerImpl* layer,
1339     const Functor& func,
1340     FindClosestMatchingLayerDataForRecursion* data_for_recursion) {
1341   for (int i = layer->children().size() - 1; i >= 0; --i) {
1342     FindClosestMatchingLayer(
1343         screen_space_point, layer->children()[i], func, data_for_recursion);
1344   }
1345
1346   float distance_to_intersection = 0.f;
1347   if (func(layer) &&
1348       PointHitsLayer(layer, screen_space_point, &distance_to_intersection) &&
1349       ((!data_for_recursion->closest_match ||
1350         distance_to_intersection > data_for_recursion->closest_distance))) {
1351     data_for_recursion->closest_distance = distance_to_intersection;
1352     data_for_recursion->closest_match = layer;
1353   }
1354 }
1355
1356 static bool ScrollsAnyDrawnRenderSurfaceLayerListMember(LayerImpl* layer) {
1357   if (!layer->scrollable())
1358     return false;
1359   if (layer->draw_properties().layer_or_descendant_is_drawn)
1360     return true;
1361
1362   if (!layer->scroll_children())
1363     return false;
1364   for (std::set<LayerImpl*>::const_iterator it =
1365            layer->scroll_children()->begin();
1366        it != layer->scroll_children()->end();
1367        ++it) {
1368     if ((*it)->draw_properties().layer_or_descendant_is_drawn)
1369       return true;
1370   }
1371   return false;
1372 }
1373
1374 struct FindScrollingLayerFunctor {
1375   bool operator()(LayerImpl* layer) const {
1376     return ScrollsAnyDrawnRenderSurfaceLayerListMember(layer);
1377   }
1378 };
1379
1380 LayerImpl* LayerTreeImpl::FindFirstScrollingLayerThatIsHitByPoint(
1381     const gfx::PointF& screen_space_point) {
1382   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1383   FindClosestMatchingLayer(screen_space_point,
1384                            root_layer(),
1385                            FindScrollingLayerFunctor(),
1386                            &data_for_recursion);
1387   return data_for_recursion.closest_match;
1388 }
1389
1390 struct HitTestVisibleScrollableOrTouchableFunctor {
1391   bool operator()(LayerImpl* layer) const {
1392     return layer->IsDrawnRenderSurfaceLayerListMember() ||
1393            ScrollsAnyDrawnRenderSurfaceLayerListMember(layer) ||
1394            !layer->touch_event_handler_region().IsEmpty() ||
1395            layer->have_wheel_event_handlers();
1396   }
1397 };
1398
1399 LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPoint(
1400     const gfx::PointF& screen_space_point) {
1401   if (!root_layer())
1402     return NULL;
1403   bool update_lcd_text = false;
1404   if (!UpdateDrawProperties(update_lcd_text))
1405     return NULL;
1406   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1407   FindClosestMatchingLayer(screen_space_point,
1408                            root_layer(),
1409                            HitTestVisibleScrollableOrTouchableFunctor(),
1410                            &data_for_recursion);
1411   return data_for_recursion.closest_match;
1412 }
1413
1414 static bool LayerHasTouchEventHandlersAt(const gfx::PointF& screen_space_point,
1415                                          LayerImpl* layer_impl) {
1416   if (layer_impl->touch_event_handler_region().IsEmpty())
1417     return false;
1418
1419   if (!PointHitsRegion(screen_space_point,
1420                        layer_impl->screen_space_transform(),
1421                        layer_impl->touch_event_handler_region(),
1422                        layer_impl->contents_scale_x(),
1423                        layer_impl->contents_scale_y()))
1424     return false;
1425
1426   // At this point, we think the point does hit the touch event handler region
1427   // on the layer, but we need to walk up the parents to ensure that the layer
1428   // was not clipped in such a way that the hit point actually should not hit
1429   // the layer.
1430   if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer_impl))
1431     return false;
1432
1433   return true;
1434 }
1435
1436 struct FindWheelEventLayerFunctor {
1437   bool operator()(LayerImpl* layer) const {
1438     return layer->have_wheel_event_handlers();
1439   }
1440 };
1441
1442 LayerImpl* LayerTreeImpl::FindLayerWithWheelHandlerThatIsHitByPoint(
1443     const gfx::PointF& screen_space_point) {
1444   if (!root_layer())
1445     return NULL;
1446   bool update_lcd_text = false;
1447   if (!UpdateDrawProperties(update_lcd_text))
1448     return NULL;
1449   FindWheelEventLayerFunctor func;
1450   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1451   FindClosestMatchingLayer(screen_space_point, root_layer(), func,
1452                            &data_for_recursion);
1453   return data_for_recursion.closest_match;
1454 }
1455
1456 struct FindTouchEventLayerFunctor {
1457   bool operator()(LayerImpl* layer) const {
1458     return LayerHasTouchEventHandlersAt(screen_space_point, layer);
1459   }
1460   const gfx::PointF screen_space_point;
1461 };
1462
1463 LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPointInTouchHandlerRegion(
1464     const gfx::PointF& screen_space_point) {
1465   if (!root_layer())
1466     return NULL;
1467   bool update_lcd_text = false;
1468   if (!UpdateDrawProperties(update_lcd_text))
1469     return NULL;
1470   FindTouchEventLayerFunctor func = {screen_space_point};
1471   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1472   FindClosestMatchingLayer(
1473       screen_space_point, root_layer(), func, &data_for_recursion);
1474   return data_for_recursion.closest_match;
1475 }
1476
1477 void LayerTreeImpl::RegisterSelection(const LayerSelectionBound& start,
1478                                       const LayerSelectionBound& end) {
1479   selection_start_ = start;
1480   selection_end_ = end;
1481 }
1482
1483 static ViewportSelectionBound ComputeViewportSelection(
1484     const LayerSelectionBound& layer_bound,
1485     LayerImpl* layer,
1486     float device_scale_factor) {
1487   ViewportSelectionBound viewport_bound;
1488   viewport_bound.type = layer_bound.type;
1489
1490   if (!layer || layer_bound.type == SELECTION_BOUND_EMPTY)
1491     return viewport_bound;
1492
1493   gfx::PointF layer_scaled_top = gfx::ScalePoint(layer_bound.edge_top,
1494                                                  layer->contents_scale_x(),
1495                                                  layer->contents_scale_y());
1496   gfx::PointF layer_scaled_bottom = gfx::ScalePoint(layer_bound.edge_bottom,
1497                                                     layer->contents_scale_x(),
1498                                                     layer->contents_scale_y());
1499
1500   bool clipped = false;
1501   gfx::PointF screen_top = MathUtil::MapPoint(
1502       layer->screen_space_transform(), layer_scaled_top, &clipped);
1503   gfx::PointF screen_bottom = MathUtil::MapPoint(
1504       layer->screen_space_transform(), layer_scaled_bottom, &clipped);
1505
1506   const float inv_scale = 1.f / device_scale_factor;
1507   viewport_bound.edge_top = gfx::ScalePoint(screen_top, inv_scale);
1508   viewport_bound.edge_bottom = gfx::ScalePoint(screen_bottom, inv_scale);
1509
1510   // The bottom edge point is used for visibility testing as it is the logical
1511   // focal point for bound selection handles (this may change in the future).
1512   // Shifting the visibility point fractionally inward ensures that neighboring
1513   // or logically coincident layers aligned to integral DPI coordinates will not
1514   // spuriously occlude the bound.
1515   gfx::Vector2dF visibility_offset = layer_scaled_top - layer_scaled_bottom;
1516   visibility_offset.Scale(device_scale_factor / visibility_offset.Length());
1517   gfx::PointF visibility_point = layer_scaled_bottom + visibility_offset;
1518   if (visibility_point.x() <= 0)
1519     visibility_point.set_x(visibility_point.x() + device_scale_factor);
1520   visibility_point = MathUtil::MapPoint(
1521       layer->screen_space_transform(), visibility_point, &clipped);
1522
1523   float intersect_distance = 0.f;
1524   viewport_bound.visible =
1525       PointHitsLayer(layer, visibility_point, &intersect_distance);
1526
1527   return viewport_bound;
1528 }
1529
1530 void LayerTreeImpl::GetViewportSelection(ViewportSelectionBound* start,
1531                                          ViewportSelectionBound* end) {
1532   DCHECK(start);
1533   DCHECK(end);
1534
1535   *start = ComputeViewportSelection(
1536       selection_start_,
1537       selection_start_.layer_id ? LayerById(selection_start_.layer_id) : NULL,
1538       device_scale_factor());
1539   if (start->type == SELECTION_BOUND_CENTER ||
1540       start->type == SELECTION_BOUND_EMPTY) {
1541     *end = *start;
1542   } else {
1543     *end = ComputeViewportSelection(
1544         selection_end_,
1545         selection_end_.layer_id ? LayerById(selection_end_.layer_id) : NULL,
1546         device_scale_factor());
1547   }
1548 }
1549
1550 void LayerTreeImpl::InputScrollAnimationFinished() {
1551   layer_tree_host_impl_->ScrollEnd();
1552 }
1553
1554 bool LayerTreeImpl::SmoothnessTakesPriority() const {
1555   return layer_tree_host_impl_->GetTreePriority() == SMOOTHNESS_TAKES_PRIORITY;
1556 }
1557
1558 BlockingTaskRunner* LayerTreeImpl::BlockingMainThreadTaskRunner() const {
1559   return proxy()->blocking_main_thread_task_runner();
1560 }
1561
1562 void LayerTreeImpl::SetPendingPageScaleAnimation(
1563     scoped_ptr<PendingPageScaleAnimation> pending_animation) {
1564   pending_page_scale_animation_ = pending_animation.Pass();
1565 }
1566
1567 scoped_ptr<PendingPageScaleAnimation>
1568     LayerTreeImpl::TakePendingPageScaleAnimation() {
1569   return pending_page_scale_animation_.Pass();
1570 }
1571
1572 }  // namespace cc