cc/trees/layer_tree_host.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_host.h"
   6
   7 #include <algorithm>
   8 #include <stack>
   9 #include <string>
  10
  11 #include "base/atomic_sequence_num.h"
  12 #include "base/bind.h"
  13 #include "base/command_line.h"
  14 #include "base/debug/trace_event.h"
  15 #include "base/message_loop/message_loop.h"
  16 #include "base/metrics/histogram.h"
  17 #include "base/stl_util.h"
  18 #include "base/strings/string_number_conversions.h"
  19 #include "cc/animation/animation_registrar.h"
  20 #include "cc/animation/layer_animation_controller.h"
  21 #include "cc/base/math_util.h"
  22 #include "cc/debug/devtools_instrumentation.h"
  23 #include "cc/debug/rendering_stats_instrumentation.h"
  24 #include "cc/input/layer_selection_bound.h"
  25 #include "cc/input/top_controls_manager.h"
  26 #include "cc/layers/heads_up_display_layer.h"
  27 #include "cc/layers/heads_up_display_layer_impl.h"
  28 #include "cc/layers/layer.h"
  29 #include "cc/layers/layer_iterator.h"
  30 #include "cc/layers/painted_scrollbar_layer.h"
  31 #include "cc/layers/render_surface.h"
  32 #include "cc/resources/prioritized_resource_manager.h"
  33 #include "cc/resources/ui_resource_request.h"
  34 #include "cc/trees/layer_tree_host_client.h"
  35 #include "cc/trees/layer_tree_host_common.h"
  36 #include "cc/trees/layer_tree_host_impl.h"
  37 #include "cc/trees/layer_tree_impl.h"
  38 #include "cc/trees/occlusion_tracker.h"
  39 #include "cc/trees/single_thread_proxy.h"
  40 #include "cc/trees/thread_proxy.h"
  41 #include "cc/trees/tree_synchronizer.h"
  42 #include "ui/gfx/size_conversions.h"
  43
  44 namespace {
  45 static base::StaticAtomicSequenceNumber s_layer_tree_host_sequence_number;
  46 }
  47
  48 namespace cc {
  49
  50 RendererCapabilities::RendererCapabilities(ResourceFormat best_texture_format,
  51                                            bool allow_partial_texture_updates,
  52                                            int max_texture_size,
  53                                            bool using_shared_memory_resources)
  54     : best_texture_format(best_texture_format),
  55       allow_partial_texture_updates(allow_partial_texture_updates),
  56       max_texture_size(max_texture_size),
  57       using_shared_memory_resources(using_shared_memory_resources) {}
  58
  59 RendererCapabilities::RendererCapabilities()
  60     : best_texture_format(RGBA_8888),
  61       allow_partial_texture_updates(false),
  62       max_texture_size(0),
  63       using_shared_memory_resources(false) {}
  64
  65 RendererCapabilities::~RendererCapabilities() {}
  66
  67 scoped_ptr<LayerTreeHost> LayerTreeHost::CreateThreaded(
  68     LayerTreeHostClient* client,
  69     SharedBitmapManager* manager,
  70     const LayerTreeSettings& settings,
  71     scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner) {
  72   DCHECK(impl_task_runner);
  73   scoped_ptr<LayerTreeHost> layer_tree_host(
  74       new LayerTreeHost(client, manager, settings));
  75   layer_tree_host->InitializeThreaded(impl_task_runner);
  76   return layer_tree_host.Pass();
  77 }
  78
  79 scoped_ptr<LayerTreeHost> LayerTreeHost::CreateSingleThreaded(
  80     LayerTreeHostClient* client,
  81     LayerTreeHostSingleThreadClient* single_thread_client,
  82     SharedBitmapManager* manager,
  83     const LayerTreeSettings& settings) {
  84   scoped_ptr<LayerTreeHost> layer_tree_host(
  85       new LayerTreeHost(client, manager, settings));
  86   layer_tree_host->InitializeSingleThreaded(single_thread_client);
  87   return layer_tree_host.Pass();
  88 }
  89
  90 LayerTreeHost::LayerTreeHost(LayerTreeHostClient* client,
  91                              SharedBitmapManager* manager,
  92                              const LayerTreeSettings& settings)
  93     : micro_benchmark_controller_(this),
  94       next_ui_resource_id_(1),
  95       animating_(false),
  96       needs_full_tree_sync_(true),
  97       client_(client),
  98       source_frame_number_(0),
  99       rendering_stats_instrumentation_(RenderingStatsInstrumentation::Create()),
 100       output_surface_lost_(true),
 101       num_failed_recreate_attempts_(0),
 102       settings_(settings),
 103       debug_state_(settings.initial_debug_state),
 104       overdraw_bottom_height_(0.f),
 105       device_scale_factor_(1.f),
 106       visible_(true),
 107       page_scale_factor_(1.f),
 108       min_page_scale_factor_(1.f),
 109       max_page_scale_factor_(1.f),
 110       has_gpu_rasterization_trigger_(false),
 111       content_is_suitable_for_gpu_rasterization_(true),
 112       gpu_rasterization_histogram_recorded_(false),
 113       background_color_(SK_ColorWHITE),
 114       has_transparent_background_(false),
 115       partial_texture_update_requests_(0),
 116       in_paint_layer_contents_(false),
 117       total_frames_used_for_lcd_text_metrics_(0),
 118       id_(s_layer_tree_host_sequence_number.GetNext() + 1),
 119       next_commit_forces_redraw_(false),
 120       shared_bitmap_manager_(manager) {
 121   if (settings_.accelerated_animation_enabled)
 122     animation_registrar_ = AnimationRegistrar::Create();
 123   rendering_stats_instrumentation_->set_record_rendering_stats(
 124       debug_state_.RecordRenderingStats());
 125 }
 126
 127 void LayerTreeHost::InitializeThreaded(
 128     scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner) {
 129   InitializeProxy(ThreadProxy::Create(this, impl_task_runner));
 130 }
 131
 132 void LayerTreeHost::InitializeSingleThreaded(
 133     LayerTreeHostSingleThreadClient* single_thread_client) {
 134   InitializeProxy(SingleThreadProxy::Create(this, single_thread_client));
 135 }
 136
 137 void LayerTreeHost::InitializeForTesting(scoped_ptr<Proxy> proxy_for_testing) {
 138   InitializeProxy(proxy_for_testing.Pass());
 139 }
 140
 141 void LayerTreeHost::InitializeProxy(scoped_ptr<Proxy> proxy) {
 142   TRACE_EVENT0("cc", "LayerTreeHost::InitializeForReal");
 143
 144   proxy_ = proxy.Pass();
 145   proxy_->Start();
 146   if (settings_.accelerated_animation_enabled) {
 147     animation_registrar_->set_supports_scroll_animations(
 148         proxy_->SupportsImplScrolling());
 149   }
 150 }
 151
 152 LayerTreeHost::~LayerTreeHost() {
 153   TRACE_EVENT0("cc", "LayerTreeHost::~LayerTreeHost");
 154
 155   overhang_ui_resource_.reset();
 156
 157   if (root_layer_.get())
 158     root_layer_->SetLayerTreeHost(NULL);
 159
 160   if (proxy_) {
 161     DCHECK(proxy_->IsMainThread());
 162     proxy_->Stop();
 163   }
 164
 165   // We must clear any pointers into the layer tree prior to destroying it.
 166   RegisterViewportLayers(NULL, NULL, NULL);
 167
 168   if (root_layer_.get()) {
 169     // The layer tree must be destroyed before the layer tree host. We've
 170     // made a contract with our animation controllers that the registrar
 171     // will outlive them, and we must make good.
 172     root_layer_ = NULL;
 173   }
 174 }
 175
 176 void LayerTreeHost::SetLayerTreeHostClientReady() {
 177   proxy_->SetLayerTreeHostClientReady();
 178 }
 179
 180 static void LayerTreeHostOnOutputSurfaceCreatedCallback(Layer* layer) {
 181   layer->OnOutputSurfaceCreated();
 182 }
 183
 184 void LayerTreeHost::OnCreateAndInitializeOutputSurfaceAttempted(bool success) {
 185   DCHECK(output_surface_lost_);
 186   TRACE_EVENT1("cc",
 187                "LayerTreeHost::OnCreateAndInitializeOutputSurfaceAttempted",
 188                "success",
 189                success);
 190
 191   if (!success) {
 192     // Tolerate a certain number of recreation failures to work around races
 193     // in the output-surface-lost machinery.
 194     ++num_failed_recreate_attempts_;
 195     if (num_failed_recreate_attempts_ >= 5)
 196       LOG(FATAL) << "Failed to create a fallback OutputSurface.";
 197     client_->DidFailToInitializeOutputSurface();
 198     return;
 199   }
 200
 201   output_surface_lost_ = false;
 202
 203   if (!contents_texture_manager_ && !settings_.impl_side_painting) {
 204     contents_texture_manager_ =
 205         PrioritizedResourceManager::Create(proxy_.get());
 206     surface_memory_placeholder_ =
 207         contents_texture_manager_->CreateTexture(gfx::Size(), RGBA_8888);
 208   }
 209
 210   if (root_layer()) {
 211     LayerTreeHostCommon::CallFunctionForSubtree(
 212         root_layer(), base::Bind(&LayerTreeHostOnOutputSurfaceCreatedCallback));
 213   }
 214
 215   client_->DidInitializeOutputSurface();
 216 }
 217
 218 void LayerTreeHost::DeleteContentsTexturesOnImplThread(
 219     ResourceProvider* resource_provider) {
 220   DCHECK(proxy_->IsImplThread());
 221   if (contents_texture_manager_)
 222     contents_texture_manager_->ClearAllMemory(resource_provider);
 223 }
 224
 225 void LayerTreeHost::DidBeginMainFrame() {
 226   client_->DidBeginMainFrame();
 227 }
 228
 229 void LayerTreeHost::UpdateClientAnimations(base::TimeTicks frame_begin_time) {
 230   animating_ = true;
 231   client_->Animate(frame_begin_time);
 232   animating_ = false;
 233 }
 234
 235 void LayerTreeHost::DidStopFlinging() {
 236   proxy_->MainThreadHasStoppedFlinging();
 237 }
 238
 239 void LayerTreeHost::Layout() {
 240   client_->Layout();
 241 }
 242
 243 void LayerTreeHost::BeginCommitOnImplThread(LayerTreeHostImpl* host_impl) {
 244   DCHECK(proxy_->IsImplThread());
 245   TRACE_EVENT0("cc", "LayerTreeHost::CommitTo");
 246 }
 247
 248 // This function commits the LayerTreeHost to an impl tree. When modifying
 249 // this function, keep in mind that the function *runs* on the impl thread! Any
 250 // code that is logically a main thread operation, e.g. deletion of a Layer,
 251 // should be delayed until the LayerTreeHost::CommitComplete, which will run
 252 // after the commit, but on the main thread.
 253 void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
 254   DCHECK(proxy_->IsImplThread());
 255
 256   // If there are linked evicted backings, these backings' resources may be put
 257   // into the impl tree, so we can't draw yet. Determine this before clearing
 258   // all evicted backings.
 259   bool new_impl_tree_has_no_evicted_resources = false;
 260   if (contents_texture_manager_) {
 261     new_impl_tree_has_no_evicted_resources =
 262         !contents_texture_manager_->LinkedEvictedBackingsExist();
 263
 264     // If the memory limit has been increased since this now-finishing
 265     // commit began, and the extra now-available memory would have been used,
 266     // then request another commit.
 267     if (contents_texture_manager_->MaxMemoryLimitBytes() <
 268             host_impl->memory_allocation_limit_bytes() &&
 269         contents_texture_manager_->MaxMemoryLimitBytes() <
 270             contents_texture_manager_->MaxMemoryNeededBytes()) {
 271       host_impl->SetNeedsCommit();
 272     }
 273
 274     host_impl->set_max_memory_needed_bytes(
 275         contents_texture_manager_->MaxMemoryNeededBytes());
 276
 277     contents_texture_manager_->UpdateBackingsState(
 278         host_impl->resource_provider());
 279     contents_texture_manager_->ReduceMemory(host_impl->resource_provider());
 280   }
 281
 282   LayerTreeImpl* sync_tree = host_impl->sync_tree();
 283
 284   if (next_commit_forces_redraw_) {
 285     sync_tree->ForceRedrawNextActivation();
 286     next_commit_forces_redraw_ = false;
 287   }
 288
 289   sync_tree->set_source_frame_number(source_frame_number());
 290
 291   if (needs_full_tree_sync_) {
 292     sync_tree->SetRootLayer(TreeSynchronizer::SynchronizeTrees(
 293         root_layer(), sync_tree->DetachLayerTree(), sync_tree));
 294   }
 295
 296   {
 297     TRACE_EVENT0("cc", "LayerTreeHost::PushProperties");
 298     TreeSynchronizer::PushProperties(root_layer(), sync_tree->root_layer());
 299   }
 300
 301   sync_tree->set_needs_full_tree_sync(needs_full_tree_sync_);
 302   needs_full_tree_sync_ = false;
 303
 304   if (hud_layer_.get()) {
 305     LayerImpl* hud_impl = LayerTreeHostCommon::FindLayerInSubtree(
 306         sync_tree->root_layer(), hud_layer_->id());
 307     sync_tree->set_hud_layer(static_cast<HeadsUpDisplayLayerImpl*>(hud_impl));
 308   } else {
 309     sync_tree->set_hud_layer(NULL);
 310   }
 311
 312   sync_tree->set_background_color(background_color_);
 313   sync_tree->set_has_transparent_background(has_transparent_background_);
 314
 315   if (page_scale_layer_ && inner_viewport_scroll_layer_) {
 316     sync_tree->SetViewportLayersFromIds(
 317         page_scale_layer_->id(),
 318         inner_viewport_scroll_layer_->id(),
 319         outer_viewport_scroll_layer_ ? outer_viewport_scroll_layer_->id()
 320                                      : Layer::INVALID_ID);
 321   } else {
 322     sync_tree->ClearViewportLayers();
 323   }
 324
 325   sync_tree->RegisterSelection(selection_start_, selection_end_);
 326
 327   float page_scale_delta =
 328       sync_tree->page_scale_delta() / sync_tree->sent_page_scale_delta();
 329   sync_tree->SetPageScaleValues(page_scale_factor_,
 330                                 min_page_scale_factor_,
 331                                 max_page_scale_factor_,
 332                                 page_scale_delta);
 333   sync_tree->set_sent_page_scale_delta(1.f);
 334
 335   sync_tree->PassSwapPromises(&swap_promise_list_);
 336
 337   host_impl->SetUseGpuRasterization(UseGpuRasterization());
 338   RecordGpuRasterizationHistogram();
 339
 340   host_impl->SetViewportSize(device_viewport_size_);
 341   host_impl->SetOverdrawBottomHeight(overdraw_bottom_height_);
 342   host_impl->SetDeviceScaleFactor(device_scale_factor_);
 343   host_impl->SetDebugState(debug_state_);
 344   if (pending_page_scale_animation_) {
 345     host_impl->StartPageScaleAnimation(
 346         pending_page_scale_animation_->target_offset,
 347         pending_page_scale_animation_->use_anchor,
 348         pending_page_scale_animation_->scale,
 349         pending_page_scale_animation_->duration);
 350     pending_page_scale_animation_.reset();
 351   }
 352
 353   if (!ui_resource_request_queue_.empty()) {
 354     sync_tree->set_ui_resource_request_queue(ui_resource_request_queue_);
 355     ui_resource_request_queue_.clear();
 356   }
 357   if (overhang_ui_resource_) {
 358     host_impl->SetOverhangUIResource(
 359         overhang_ui_resource_->id(),
 360         GetUIResourceSize(overhang_ui_resource_->id()));
 361   }
 362
 363   DCHECK(!sync_tree->ViewportSizeInvalid());
 364
 365   if (new_impl_tree_has_no_evicted_resources) {
 366     if (sync_tree->ContentsTexturesPurged())
 367       sync_tree->ResetContentsTexturesPurged();
 368   }
 369
 370   micro_benchmark_controller_.ScheduleImplBenchmarks(host_impl);
 371 }
 372
 373 void LayerTreeHost::WillCommit() {
 374   client_->WillCommit();
 375 }
 376
 377 void LayerTreeHost::UpdateHudLayer() {
 378   if (debug_state_.ShowHudInfo()) {
 379     if (!hud_layer_.get())
 380       hud_layer_ = HeadsUpDisplayLayer::Create();
 381
 382     if (root_layer_.get() && !hud_layer_->parent())
 383       root_layer_->AddChild(hud_layer_);
 384   } else if (hud_layer_.get()) {
 385     hud_layer_->RemoveFromParent();
 386     hud_layer_ = NULL;
 387   }
 388 }
 389
 390 void LayerTreeHost::CommitComplete() {
 391   source_frame_number_++;
 392   client_->DidCommit();
 393 }
 394
 395 scoped_ptr<OutputSurface> LayerTreeHost::CreateOutputSurface() {
 396   return client_->CreateOutputSurface(num_failed_recreate_attempts_ >= 4);
 397 }
 398
 399 scoped_ptr<LayerTreeHostImpl> LayerTreeHost::CreateLayerTreeHostImpl(
 400     LayerTreeHostImplClient* client) {
 401   DCHECK(proxy_->IsImplThread());
 402   scoped_ptr<LayerTreeHostImpl> host_impl =
 403       LayerTreeHostImpl::Create(settings_,
 404                                 client,
 405                                 proxy_.get(),
 406                                 rendering_stats_instrumentation_.get(),
 407                                 shared_bitmap_manager_,
 408                                 id_);
 409   host_impl->SetUseGpuRasterization(UseGpuRasterization());
 410   shared_bitmap_manager_ = NULL;
 411   if (settings_.calculate_top_controls_position &&
 412       host_impl->top_controls_manager()) {
 413     top_controls_manager_weak_ptr_ =
 414         host_impl->top_controls_manager()->AsWeakPtr();
 415   }
 416   input_handler_weak_ptr_ = host_impl->AsWeakPtr();
 417   return host_impl.Pass();
 418 }
 419
 420 void LayerTreeHost::DidLoseOutputSurface() {
 421   TRACE_EVENT0("cc", "LayerTreeHost::DidLoseOutputSurface");
 422   DCHECK(proxy_->IsMainThread());
 423
 424   if (output_surface_lost_)
 425     return;
 426
 427   num_failed_recreate_attempts_ = 0;
 428   output_surface_lost_ = true;
 429   SetNeedsCommit();
 430 }
 431
 432 void LayerTreeHost::FinishAllRendering() {
 433   proxy_->FinishAllRendering();
 434 }
 435
 436 void LayerTreeHost::SetDeferCommits(bool defer_commits) {
 437   proxy_->SetDeferCommits(defer_commits);
 438 }
 439
 440 void LayerTreeHost::DidDeferCommit() {}
 441
 442 void LayerTreeHost::SetNeedsDisplayOnAllLayers() {
 443   std::stack<Layer*> layer_stack;
 444   layer_stack.push(root_layer());
 445   while (!layer_stack.empty()) {
 446     Layer* current_layer = layer_stack.top();
 447     layer_stack.pop();
 448     current_layer->SetNeedsDisplay();
 449     for (unsigned int i = 0; i < current_layer->children().size(); i++) {
 450       layer_stack.push(current_layer->child_at(i));
 451     }
 452   }
 453 }
 454
 455 const RendererCapabilities& LayerTreeHost::GetRendererCapabilities() const {
 456   return proxy_->GetRendererCapabilities();
 457 }
 458
 459 void LayerTreeHost::SetNeedsAnimate() {
 460   proxy_->SetNeedsAnimate();
 461   NotifySwapPromiseMonitorsOfSetNeedsCommit();
 462 }
 463
 464 void LayerTreeHost::SetNeedsUpdateLayers() {
 465   proxy_->SetNeedsUpdateLayers();
 466   NotifySwapPromiseMonitorsOfSetNeedsCommit();
 467 }
 468
 469 void LayerTreeHost::SetNeedsCommit() {
 470   if (!prepaint_callback_.IsCancelled()) {
 471     TRACE_EVENT_INSTANT0("cc",
 472                          "LayerTreeHost::SetNeedsCommit::cancel prepaint",
 473                          TRACE_EVENT_SCOPE_THREAD);
 474     prepaint_callback_.Cancel();
 475   }
 476   proxy_->SetNeedsCommit();
 477   NotifySwapPromiseMonitorsOfSetNeedsCommit();
 478 }
 479
 480 void LayerTreeHost::SetNeedsFullTreeSync() {
 481   needs_full_tree_sync_ = true;
 482   SetNeedsCommit();
 483 }
 484
 485 void LayerTreeHost::SetNeedsRedraw() {
 486   SetNeedsRedrawRect(gfx::Rect(device_viewport_size_));
 487 }
 488
 489 void LayerTreeHost::SetNeedsRedrawRect(const gfx::Rect& damage_rect) {
 490   proxy_->SetNeedsRedraw(damage_rect);
 491 }
 492
 493 bool LayerTreeHost::CommitRequested() const {
 494   return proxy_->CommitRequested();
 495 }
 496
 497 bool LayerTreeHost::BeginMainFrameRequested() const {
 498   return proxy_->BeginMainFrameRequested();
 499 }
 500
 501
 502 void LayerTreeHost::SetNextCommitWaitsForActivation() {
 503   proxy_->SetNextCommitWaitsForActivation();
 504 }
 505
 506 void LayerTreeHost::SetNextCommitForcesRedraw() {
 507   next_commit_forces_redraw_ = true;
 508 }
 509
 510 void LayerTreeHost::SetAnimationEvents(
 511     scoped_ptr<AnimationEventsVector> events) {
 512   DCHECK(proxy_->IsMainThread());
 513   for (size_t event_index = 0; event_index < events->size(); ++event_index) {
 514     int event_layer_id = (*events)[event_index].layer_id;
 515
 516     // Use the map of all controllers, not just active ones, since non-active
 517     // controllers may still receive events for impl-only animations.
 518     const AnimationRegistrar::AnimationControllerMap& animation_controllers =
 519         animation_registrar_->all_animation_controllers();
 520     AnimationRegistrar::AnimationControllerMap::const_iterator iter =
 521         animation_controllers.find(event_layer_id);
 522     if (iter != animation_controllers.end()) {
 523       switch ((*events)[event_index].type) {
 524         case AnimationEvent::Started:
 525           (*iter).second->NotifyAnimationStarted((*events)[event_index]);
 526           break;
 527
 528         case AnimationEvent::Finished:
 529           (*iter).second->NotifyAnimationFinished((*events)[event_index]);
 530           break;
 531
 532         case AnimationEvent::Aborted:
 533           (*iter).second->NotifyAnimationAborted((*events)[event_index]);
 534           break;
 535
 536         case AnimationEvent::PropertyUpdate:
 537           (*iter).second->NotifyAnimationPropertyUpdate((*events)[event_index]);
 538           break;
 539       }
 540     }
 541   }
 542 }
 543
 544 void LayerTreeHost::SetRootLayer(scoped_refptr<Layer> root_layer) {
 545   if (root_layer_.get() == root_layer.get())
 546     return;
 547
 548   if (root_layer_.get())
 549     root_layer_->SetLayerTreeHost(NULL);
 550   root_layer_ = root_layer;
 551   if (root_layer_.get()) {
 552     DCHECK(!root_layer_->parent());
 553     root_layer_->SetLayerTreeHost(this);
 554   }
 555
 556   if (hud_layer_.get())
 557     hud_layer_->RemoveFromParent();
 558
 559   // Reset gpu rasterization flag.
 560   // This flag is sticky until a new tree comes along.
 561   content_is_suitable_for_gpu_rasterization_ = true;
 562   gpu_rasterization_histogram_recorded_ = false;
 563
 564   SetNeedsFullTreeSync();
 565 }
 566
 567 void LayerTreeHost::SetDebugState(const LayerTreeDebugState& debug_state) {
 568   LayerTreeDebugState new_debug_state =
 569       LayerTreeDebugState::Unite(settings_.initial_debug_state, debug_state);
 570
 571   if (LayerTreeDebugState::Equal(debug_state_, new_debug_state))
 572     return;
 573
 574   debug_state_ = new_debug_state;
 575
 576   rendering_stats_instrumentation_->set_record_rendering_stats(
 577       debug_state_.RecordRenderingStats());
 578
 579   SetNeedsCommit();
 580   proxy_->SetDebugState(debug_state);
 581 }
 582
 583 bool LayerTreeHost::UseGpuRasterization() const {
 584   if (settings_.gpu_rasterization_forced) {
 585     return true;
 586   } else if (settings_.gpu_rasterization_enabled) {
 587     return has_gpu_rasterization_trigger_ &&
 588            content_is_suitable_for_gpu_rasterization_;
 589   } else {
 590     return false;
 591   }
 592 }
 593
 594 void LayerTreeHost::SetHasGpuRasterizationTrigger(bool has_trigger) {
 595   if (has_trigger == has_gpu_rasterization_trigger_)
 596     return;
 597
 598   has_gpu_rasterization_trigger_ = has_trigger;
 599   TRACE_EVENT_INSTANT1("cc",
 600                        "LayerTreeHost::SetHasGpuRasterizationTrigger",
 601                        TRACE_EVENT_SCOPE_THREAD,
 602                        "has_trigger",
 603                        has_gpu_rasterization_trigger_);
 604 }
 605
 606 void LayerTreeHost::SetViewportSize(const gfx::Size& device_viewport_size) {
 607   if (device_viewport_size == device_viewport_size_)
 608     return;
 609
 610   device_viewport_size_ = device_viewport_size;
 611
 612   SetNeedsCommit();
 613 }
 614
 615 void LayerTreeHost::SetOverdrawBottomHeight(float overdraw_bottom_height) {
 616   if (overdraw_bottom_height_ == overdraw_bottom_height)
 617     return;
 618
 619   overdraw_bottom_height_ = overdraw_bottom_height;
 620   SetNeedsCommit();
 621 }
 622
 623 void LayerTreeHost::ApplyPageScaleDeltaFromImplSide(float page_scale_delta) {
 624   DCHECK(CommitRequested());
 625   page_scale_factor_ *= page_scale_delta;
 626 }
 627
 628 void LayerTreeHost::SetPageScaleFactorAndLimits(float page_scale_factor,
 629                                                 float min_page_scale_factor,
 630                                                 float max_page_scale_factor) {
 631   if (page_scale_factor == page_scale_factor_ &&
 632       min_page_scale_factor == min_page_scale_factor_ &&
 633       max_page_scale_factor == max_page_scale_factor_)
 634     return;
 635
 636   page_scale_factor_ = page_scale_factor;
 637   min_page_scale_factor_ = min_page_scale_factor;
 638   max_page_scale_factor_ = max_page_scale_factor;
 639   SetNeedsCommit();
 640 }
 641
 642 void LayerTreeHost::SetOverhangBitmap(const SkBitmap& bitmap) {
 643   DCHECK(bitmap.width() && bitmap.height());
 644   DCHECK_EQ(bitmap.bytesPerPixel(), 4);
 645
 646   SkBitmap bitmap_copy;
 647   if (bitmap.isImmutable()) {
 648     bitmap_copy = bitmap;
 649   } else {
 650     bitmap.copyTo(&bitmap_copy);
 651     bitmap_copy.setImmutable();
 652   }
 653
 654   UIResourceBitmap overhang_bitmap(bitmap_copy);
 655   overhang_bitmap.SetWrapMode(UIResourceBitmap::REPEAT);
 656   overhang_ui_resource_ = ScopedUIResource::Create(this, overhang_bitmap);
 657 }
 658
 659 void LayerTreeHost::SetVisible(bool visible) {
 660   if (visible_ == visible)
 661     return;
 662   visible_ = visible;
 663   if (!visible)
 664     ReduceMemoryUsage();
 665   proxy_->SetVisible(visible);
 666 }
 667
 668 void LayerTreeHost::StartPageScaleAnimation(const gfx::Vector2d& target_offset,
 669                                             bool use_anchor,
 670                                             float scale,
 671                                             base::TimeDelta duration) {
 672   pending_page_scale_animation_.reset(new PendingPageScaleAnimation);
 673   pending_page_scale_animation_->target_offset = target_offset;
 674   pending_page_scale_animation_->use_anchor = use_anchor;
 675   pending_page_scale_animation_->scale = scale;
 676   pending_page_scale_animation_->duration = duration;
 677
 678   SetNeedsCommit();
 679 }
 680
 681 void LayerTreeHost::NotifyInputThrottledUntilCommit() {
 682   proxy_->NotifyInputThrottledUntilCommit();
 683 }
 684
 685 void LayerTreeHost::Composite(base::TimeTicks frame_begin_time) {
 686   DCHECK(!proxy_->HasImplThread());
 687   SingleThreadProxy* proxy = static_cast<SingleThreadProxy*>(proxy_.get());
 688
 689   if (output_surface_lost_)
 690     proxy->CreateAndInitializeOutputSurface();
 691   if (output_surface_lost_)
 692     return;
 693
 694   proxy->CompositeImmediately(frame_begin_time);
 695 }
 696
 697 bool LayerTreeHost::UpdateLayers(ResourceUpdateQueue* queue) {
 698   DCHECK(!output_surface_lost_);
 699
 700   if (!root_layer())
 701     return false;
 702
 703   DCHECK(!root_layer()->parent());
 704
 705   bool result = UpdateLayers(root_layer(), queue);
 706
 707   micro_benchmark_controller_.DidUpdateLayers();
 708
 709   return result || next_commit_forces_redraw_;
 710 }
 711
 712 static Layer* FindFirstScrollableLayer(Layer* layer) {
 713   if (!layer)
 714     return NULL;
 715
 716   if (layer->scrollable())
 717     return layer;
 718
 719   for (size_t i = 0; i < layer->children().size(); ++i) {
 720     Layer* found = FindFirstScrollableLayer(layer->children()[i].get());
 721     if (found)
 722       return found;
 723   }
 724
 725   return NULL;
 726 }
 727
 728 void LayerTreeHost::RecordGpuRasterizationHistogram() {
 729   // Gpu rasterization is only supported when impl-side painting is enabled.
 730   if (gpu_rasterization_histogram_recorded_ || !settings_.impl_side_painting)
 731     return;
 732
 733   // Record how widely gpu rasterization is enabled.
 734   // This number takes device/gpu whitelisting/backlisting into account.
 735   // Note that we do not consider the forced gpu rasterization mode, which is
 736   // mostly used for debugging purposes.
 737   UMA_HISTOGRAM_BOOLEAN("Renderer4.GpuRasterizationEnabled",
 738                         settings_.gpu_rasterization_enabled);
 739   if (settings_.gpu_rasterization_enabled) {
 740     UMA_HISTOGRAM_BOOLEAN("Renderer4.GpuRasterizationTriggered",
 741                           has_gpu_rasterization_trigger_);
 742     UMA_HISTOGRAM_BOOLEAN("Renderer4.GpuRasterizationSuitableContent",
 743                           content_is_suitable_for_gpu_rasterization_);
 744     // Record how many pages actually get gpu rasterization when enabled.
 745     UMA_HISTOGRAM_BOOLEAN("Renderer4.GpuRasterizationUsed",
 746                           (has_gpu_rasterization_trigger_ &&
 747                            content_is_suitable_for_gpu_rasterization_));
 748   }
 749
 750   gpu_rasterization_histogram_recorded_ = true;
 751 }
 752
 753 void LayerTreeHost::CalculateLCDTextMetricsCallback(Layer* layer) {
 754   if (!layer->SupportsLCDText())
 755     return;
 756
 757   lcd_text_metrics_.total_num_cc_layers++;
 758   if (layer->draw_properties().can_use_lcd_text) {
 759     lcd_text_metrics_.total_num_cc_layers_can_use_lcd_text++;
 760     if (layer->contents_opaque())
 761       lcd_text_metrics_.total_num_cc_layers_will_use_lcd_text++;
 762   }
 763 }
 764
 765 bool LayerTreeHost::UsingSharedMemoryResources() {
 766   return GetRendererCapabilities().using_shared_memory_resources;
 767 }
 768
 769 bool LayerTreeHost::UpdateLayers(Layer* root_layer,
 770                                  ResourceUpdateQueue* queue) {
 771   TRACE_EVENT1("cc", "LayerTreeHost::UpdateLayers",
 772                "source_frame_number", source_frame_number());
 773
 774   RenderSurfaceLayerList update_list;
 775   {
 776     UpdateHudLayer();
 777
 778     Layer* root_scroll = FindFirstScrollableLayer(root_layer);
 779     Layer* page_scale_layer = page_scale_layer_;
 780     if (!page_scale_layer && root_scroll)
 781       page_scale_layer = root_scroll->parent();
 782
 783     if (hud_layer_) {
 784       hud_layer_->PrepareForCalculateDrawProperties(
 785           device_viewport_size(), device_scale_factor_);
 786     }
 787
 788     TRACE_EVENT0("cc", "LayerTreeHost::UpdateLayers::CalcDrawProps");
 789     bool can_render_to_separate_surface = true;
 790     // TODO(vmpstr): Passing 0 as the current render surface layer list id means
 791     // that we won't be able to detect if a layer is part of |update_list|.
 792     // Change this if this information is required.
 793     int render_surface_layer_list_id = 0;
 794     LayerTreeHostCommon::CalcDrawPropsMainInputs inputs(
 795         root_layer,
 796         device_viewport_size(),
 797         gfx::Transform(),
 798         device_scale_factor_,
 799         page_scale_factor_,
 800         page_scale_layer,
 801         GetRendererCapabilities().max_texture_size,
 802         settings_.can_use_lcd_text,
 803         can_render_to_separate_surface,
 804         settings_.layer_transforms_should_scale_layer_contents,
 805         &update_list,
 806         render_surface_layer_list_id);
 807     LayerTreeHostCommon::CalculateDrawProperties(&inputs);
 808
 809     if (total_frames_used_for_lcd_text_metrics_ <=
 810         kTotalFramesToUseForLCDTextMetrics) {
 811       LayerTreeHostCommon::CallFunctionForSubtree(
 812           root_layer,
 813           base::Bind(&LayerTreeHost::CalculateLCDTextMetricsCallback,
 814                      base::Unretained(this)));
 815       total_frames_used_for_lcd_text_metrics_++;
 816     }
 817
 818     if (total_frames_used_for_lcd_text_metrics_ ==
 819         kTotalFramesToUseForLCDTextMetrics) {
 820       total_frames_used_for_lcd_text_metrics_++;
 821
 822       UMA_HISTOGRAM_PERCENTAGE(
 823           "Renderer4.LCDText.PercentageOfCandidateLayers",
 824           lcd_text_metrics_.total_num_cc_layers_can_use_lcd_text * 100.0 /
 825           lcd_text_metrics_.total_num_cc_layers);
 826       UMA_HISTOGRAM_PERCENTAGE(
 827           "Renderer4.LCDText.PercentageOfAALayers",
 828           lcd_text_metrics_.total_num_cc_layers_will_use_lcd_text * 100.0 /
 829           lcd_text_metrics_.total_num_cc_layers_can_use_lcd_text);
 830     }
 831   }
 832
 833   // Reset partial texture update requests.
 834   partial_texture_update_requests_ = 0;
 835
 836   bool did_paint_content = false;
 837   bool need_more_updates = false;
 838   PaintLayerContents(
 839       update_list, queue, &did_paint_content, &need_more_updates);
 840   if (need_more_updates) {
 841     TRACE_EVENT0("cc", "LayerTreeHost::UpdateLayers::posting prepaint task");
 842     prepaint_callback_.Reset(base::Bind(&LayerTreeHost::TriggerPrepaint,
 843                                         base::Unretained(this)));
 844     static base::TimeDelta prepaint_delay =
 845         base::TimeDelta::FromMilliseconds(100);
 846     base::MessageLoop::current()->PostDelayedTask(
 847         FROM_HERE, prepaint_callback_.callback(), prepaint_delay);
 848   }
 849
 850   return did_paint_content;
 851 }
 852
 853 void LayerTreeHost::TriggerPrepaint() {
 854   prepaint_callback_.Cancel();
 855   TRACE_EVENT0("cc", "LayerTreeHost::TriggerPrepaint");
 856   SetNeedsCommit();
 857 }
 858
 859 static void LayerTreeHostReduceMemoryCallback(Layer* layer) {
 860   layer->ReduceMemoryUsage();
 861 }
 862
 863 void LayerTreeHost::ReduceMemoryUsage() {
 864   if (!root_layer())
 865     return;
 866
 867   LayerTreeHostCommon::CallFunctionForSubtree(
 868       root_layer(),
 869       base::Bind(&LayerTreeHostReduceMemoryCallback));
 870 }
 871
 872 void LayerTreeHost::SetPrioritiesForSurfaces(size_t surface_memory_bytes) {
 873   DCHECK(surface_memory_placeholder_);
 874
 875   // Surfaces have a place holder for their memory since they are managed
 876   // independantly but should still be tracked and reduce other memory usage.
 877   surface_memory_placeholder_->SetTextureManager(
 878       contents_texture_manager_.get());
 879   surface_memory_placeholder_->set_request_priority(
 880       PriorityCalculator::RenderSurfacePriority());
 881   surface_memory_placeholder_->SetToSelfManagedMemoryPlaceholder(
 882       surface_memory_bytes);
 883 }
 884
 885 void LayerTreeHost::SetPrioritiesForLayers(
 886     const RenderSurfaceLayerList& update_list) {
 887   PriorityCalculator calculator;
 888   typedef LayerIterator<Layer> LayerIteratorType;
 889   LayerIteratorType end = LayerIteratorType::End(&update_list);
 890   for (LayerIteratorType it = LayerIteratorType::Begin(&update_list);
 891        it != end;
 892        ++it) {
 893     if (it.represents_itself()) {
 894       it->SetTexturePriorities(calculator);
 895     } else if (it.represents_target_render_surface()) {
 896       if (it->mask_layer())
 897         it->mask_layer()->SetTexturePriorities(calculator);
 898       if (it->replica_layer() && it->replica_layer()->mask_layer())
 899         it->replica_layer()->mask_layer()->SetTexturePriorities(calculator);
 900     }
 901   }
 902 }
 903
 904 void LayerTreeHost::PrioritizeTextures(
 905     const RenderSurfaceLayerList& render_surface_layer_list) {
 906   if (!contents_texture_manager_)
 907     return;
 908
 909   contents_texture_manager_->ClearPriorities();
 910
 911   size_t memory_for_render_surfaces_metric =
 912       CalculateMemoryForRenderSurfaces(render_surface_layer_list);
 913
 914   SetPrioritiesForLayers(render_surface_layer_list);
 915   SetPrioritiesForSurfaces(memory_for_render_surfaces_metric);
 916
 917   contents_texture_manager_->PrioritizeTextures();
 918 }
 919
 920 size_t LayerTreeHost::CalculateMemoryForRenderSurfaces(
 921     const RenderSurfaceLayerList& update_list) {
 922   size_t readback_bytes = 0;
 923   size_t max_background_texture_bytes = 0;
 924   size_t contents_texture_bytes = 0;
 925
 926   // Start iteration at 1 to skip the root surface as it does not have a texture
 927   // cost.
 928   for (size_t i = 1; i < update_list.size(); ++i) {
 929     Layer* render_surface_layer = update_list.at(i);
 930     RenderSurface* render_surface = render_surface_layer->render_surface();
 931
 932     size_t bytes =
 933         Resource::MemorySizeBytes(render_surface->content_rect().size(),
 934                                   RGBA_8888);
 935     contents_texture_bytes += bytes;
 936
 937     if (render_surface_layer->background_filters().IsEmpty())
 938       continue;
 939
 940     if (bytes > max_background_texture_bytes)
 941       max_background_texture_bytes = bytes;
 942     if (!readback_bytes) {
 943       readback_bytes = Resource::MemorySizeBytes(device_viewport_size_,
 944                                                  RGBA_8888);
 945     }
 946   }
 947   return readback_bytes + max_background_texture_bytes + contents_texture_bytes;
 948 }
 949
 950 void LayerTreeHost::PaintMasksForRenderSurface(Layer* render_surface_layer,
 951                                                ResourceUpdateQueue* queue,
 952                                                bool* did_paint_content,
 953                                                bool* need_more_updates) {
 954   // Note: Masks and replicas only exist for layers that own render surfaces. If
 955   // we reach this point in code, we already know that at least something will
 956   // be drawn into this render surface, so the mask and replica should be
 957   // painted.
 958
 959   Layer* mask_layer = render_surface_layer->mask_layer();
 960   if (mask_layer) {
 961     *did_paint_content |= mask_layer->Update(queue, NULL);
 962     *need_more_updates |= mask_layer->NeedMoreUpdates();
 963   }
 964
 965   Layer* replica_mask_layer =
 966       render_surface_layer->replica_layer() ?
 967       render_surface_layer->replica_layer()->mask_layer() : NULL;
 968   if (replica_mask_layer) {
 969     *did_paint_content |= replica_mask_layer->Update(queue, NULL);
 970     *need_more_updates |= replica_mask_layer->NeedMoreUpdates();
 971   }
 972 }
 973
 974 void LayerTreeHost::PaintLayerContents(
 975     const RenderSurfaceLayerList& render_surface_layer_list,
 976     ResourceUpdateQueue* queue,
 977     bool* did_paint_content,
 978     bool* need_more_updates) {
 979   OcclusionTracker<Layer> occlusion_tracker(
 980       root_layer_->render_surface()->content_rect());
 981   occlusion_tracker.set_minimum_tracking_size(
 982       settings_.minimum_occlusion_tracking_size);
 983
 984   PrioritizeTextures(render_surface_layer_list);
 985
 986   in_paint_layer_contents_ = true;
 987
 988   // Iterates front-to-back to allow for testing occlusion and performing
 989   // culling during the tree walk.
 990   typedef LayerIterator<Layer> LayerIteratorType;
 991   LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list);
 992   for (LayerIteratorType it =
 993            LayerIteratorType::Begin(&render_surface_layer_list);
 994        it != end;
 995        ++it) {
 996     occlusion_tracker.EnterLayer(it);
 997
 998     if (it.represents_target_render_surface()) {
 999       PaintMasksForRenderSurface(
1000           *it, queue, did_paint_content, need_more_updates);
1001     } else if (it.represents_itself()) {
1002       DCHECK(!it->paint_properties().bounds.IsEmpty());
1003       *did_paint_content |= it->Update(queue, &occlusion_tracker);
1004       *need_more_updates |= it->NeedMoreUpdates();
1005       // Note the '&&' with previous is-suitable state.
1006       // This means that once the layer-tree becomes unsuitable for gpu
1007       // rasterization due to some content, it will continue to be unsuitable
1008       // even if that content is replaced by gpu-friendly content.
1009       // This is to avoid switching back-and-forth between gpu and sw
1010       // rasterization which may be both bad for performance and visually
1011       // jarring.
1012       content_is_suitable_for_gpu_rasterization_ &=
1013           it->IsSuitableForGpuRasterization();
1014     }
1015
1016     occlusion_tracker.LeaveLayer(it);
1017   }
1018
1019   in_paint_layer_contents_ = false;
1020 }
1021
1022 void LayerTreeHost::ApplyScrollAndScale(const ScrollAndScaleSet& info) {
1023   if (!root_layer_.get())
1024     return;
1025
1026   gfx::Vector2d inner_viewport_scroll_delta;
1027   gfx::Vector2d outer_viewport_scroll_delta;
1028
1029   for (size_t i = 0; i < info.scrolls.size(); ++i) {
1030     Layer* layer =
1031         LayerTreeHostCommon::FindLayerInSubtree(root_layer_.get(),
1032                                                 info.scrolls[i].layer_id);
1033     if (!layer)
1034       continue;
1035     if (layer == outer_viewport_scroll_layer_.get()) {
1036       outer_viewport_scroll_delta += info.scrolls[i].scroll_delta;
1037     } else if (layer == inner_viewport_scroll_layer_.get()) {
1038       inner_viewport_scroll_delta += info.scrolls[i].scroll_delta;
1039     } else {
1040       layer->SetScrollOffsetFromImplSide(layer->scroll_offset() +
1041                                          info.scrolls[i].scroll_delta);
1042     }
1043   }
1044
1045   if (!inner_viewport_scroll_delta.IsZero() ||
1046       !outer_viewport_scroll_delta.IsZero() || info.page_scale_delta != 1.f) {
1047     // SetScrollOffsetFromImplSide above could have destroyed the tree,
1048     // so re-get this layer before doing anything to it.
1049
1050     // Preemptively apply the scroll offset and scale delta here before sending
1051     // it to the client.  If the client comes back and sets it to the same
1052     // value, then the layer can early out without needing a full commit.
1053     DCHECK(inner_viewport_scroll_layer_);  // We should always have this.
1054
1055     inner_viewport_scroll_layer_->SetScrollOffsetFromImplSide(
1056         inner_viewport_scroll_layer_->scroll_offset() +
1057         inner_viewport_scroll_delta);
1058     if (outer_viewport_scroll_layer_) {
1059       outer_viewport_scroll_layer_->SetScrollOffsetFromImplSide(
1060           outer_viewport_scroll_layer_->scroll_offset() +
1061           outer_viewport_scroll_delta);
1062     }
1063     ApplyPageScaleDeltaFromImplSide(info.page_scale_delta);
1064
1065     client_->ApplyScrollAndScale(
1066         inner_viewport_scroll_delta + outer_viewport_scroll_delta,
1067         info.page_scale_delta);
1068   }
1069 }
1070
1071 void LayerTreeHost::StartRateLimiter() {
1072   if (animating_)
1073     return;
1074
1075   if (!rate_limit_timer_.IsRunning()) {
1076     rate_limit_timer_.Start(FROM_HERE,
1077                             base::TimeDelta(),
1078                             this,
1079                             &LayerTreeHost::RateLimit);
1080   }
1081 }
1082
1083 void LayerTreeHost::StopRateLimiter() {
1084   rate_limit_timer_.Stop();
1085 }
1086
1087 void LayerTreeHost::RateLimit() {
1088   // Force a no-op command on the compositor context, so that any ratelimiting
1089   // commands will wait for the compositing context, and therefore for the
1090   // SwapBuffers.
1091   proxy_->ForceSerializeOnSwapBuffers();
1092   client_->RateLimitSharedMainThreadContext();
1093 }
1094
1095 bool LayerTreeHost::AlwaysUsePartialTextureUpdates() {
1096   if (!proxy_->GetRendererCapabilities().allow_partial_texture_updates)
1097     return false;
1098   return !proxy_->HasImplThread();
1099 }
1100
1101 size_t LayerTreeHost::MaxPartialTextureUpdates() const {
1102   size_t max_partial_texture_updates = 0;
1103   if (proxy_->GetRendererCapabilities().allow_partial_texture_updates &&
1104       !settings_.impl_side_painting) {
1105     max_partial_texture_updates =
1106         std::min(settings_.max_partial_texture_updates,
1107                  proxy_->MaxPartialTextureUpdates());
1108   }
1109   return max_partial_texture_updates;
1110 }
1111
1112 bool LayerTreeHost::RequestPartialTextureUpdate() {
1113   if (partial_texture_update_requests_ >= MaxPartialTextureUpdates())
1114     return false;
1115
1116   partial_texture_update_requests_++;
1117   return true;
1118 }
1119
1120 void LayerTreeHost::SetDeviceScaleFactor(float device_scale_factor) {
1121   if (device_scale_factor == device_scale_factor_)
1122     return;
1123   device_scale_factor_ = device_scale_factor;
1124
1125   SetNeedsCommit();
1126 }
1127
1128 void LayerTreeHost::UpdateTopControlsState(TopControlsState constraints,
1129                                            TopControlsState current,
1130                                            bool animate) {
1131   if (!settings_.calculate_top_controls_position)
1132     return;
1133
1134   // Top controls are only used in threaded mode.
1135   proxy_->ImplThreadTaskRunner()->PostTask(
1136       FROM_HERE,
1137       base::Bind(&TopControlsManager::UpdateTopControlsState,
1138                  top_controls_manager_weak_ptr_,
1139                  constraints,
1140                  current,
1141                  animate));
1142 }
1143
1144 scoped_ptr<base::Value> LayerTreeHost::AsValue() const {
1145   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
1146   state->Set("proxy", proxy_->AsValue().release());
1147   return state.PassAs<base::Value>();
1148 }
1149
1150 void LayerTreeHost::AnimateLayers(base::TimeTicks monotonic_time) {
1151   if (!settings_.accelerated_animation_enabled ||
1152       animation_registrar_->active_animation_controllers().empty())
1153     return;
1154
1155   TRACE_EVENT0("cc", "LayerTreeHost::AnimateLayers");
1156
1157   AnimationRegistrar::AnimationControllerMap copy =
1158       animation_registrar_->active_animation_controllers();
1159   for (AnimationRegistrar::AnimationControllerMap::iterator iter = copy.begin();
1160        iter != copy.end();
1161        ++iter) {
1162     (*iter).second->Animate(monotonic_time);
1163     bool start_ready_animations = true;
1164     (*iter).second->UpdateState(start_ready_animations, NULL);
1165   }
1166 }
1167
1168 UIResourceId LayerTreeHost::CreateUIResource(UIResourceClient* client) {
1169   DCHECK(client);
1170
1171   UIResourceId next_id = next_ui_resource_id_++;
1172   DCHECK(ui_resource_client_map_.find(next_id) ==
1173          ui_resource_client_map_.end());
1174
1175   bool resource_lost = false;
1176   UIResourceRequest request(UIResourceRequest::UIResourceCreate,
1177                             next_id,
1178                             client->GetBitmap(next_id, resource_lost));
1179   ui_resource_request_queue_.push_back(request);
1180
1181   UIResourceClientData data;
1182   data.client = client;
1183   data.size = request.GetBitmap().GetSize();
1184
1185   ui_resource_client_map_[request.GetId()] = data;
1186   return request.GetId();
1187 }
1188
1189 // Deletes a UI resource.  May safely be called more than once.
1190 void LayerTreeHost::DeleteUIResource(UIResourceId uid) {
1191   UIResourceClientMap::iterator iter = ui_resource_client_map_.find(uid);
1192   if (iter == ui_resource_client_map_.end())
1193     return;
1194
1195   UIResourceRequest request(UIResourceRequest::UIResourceDelete, uid);
1196   ui_resource_request_queue_.push_back(request);
1197   ui_resource_client_map_.erase(iter);
1198 }
1199
1200 void LayerTreeHost::RecreateUIResources() {
1201   for (UIResourceClientMap::iterator iter = ui_resource_client_map_.begin();
1202        iter != ui_resource_client_map_.end();
1203        ++iter) {
1204     UIResourceId uid = iter->first;
1205     const UIResourceClientData& data = iter->second;
1206     bool resource_lost = true;
1207     UIResourceRequest request(UIResourceRequest::UIResourceCreate,
1208                               uid,
1209                               data.client->GetBitmap(uid, resource_lost));
1210     ui_resource_request_queue_.push_back(request);
1211   }
1212 }
1213
1214 // Returns the size of a resource given its id.
1215 gfx::Size LayerTreeHost::GetUIResourceSize(UIResourceId uid) const {
1216   UIResourceClientMap::const_iterator iter = ui_resource_client_map_.find(uid);
1217   if (iter == ui_resource_client_map_.end())
1218     return gfx::Size();
1219
1220   const UIResourceClientData& data = iter->second;
1221   return data.size;
1222 }
1223
1224 void LayerTreeHost::RegisterViewportLayers(
1225     scoped_refptr<Layer> page_scale_layer,
1226     scoped_refptr<Layer> inner_viewport_scroll_layer,
1227     scoped_refptr<Layer> outer_viewport_scroll_layer) {
1228   page_scale_layer_ = page_scale_layer;
1229   inner_viewport_scroll_layer_ = inner_viewport_scroll_layer;
1230   outer_viewport_scroll_layer_ = outer_viewport_scroll_layer;
1231 }
1232
1233 void LayerTreeHost::RegisterSelection(const LayerSelectionBound& start,
1234                                       const LayerSelectionBound& end) {
1235   if (selection_start_ == start && selection_end_ == end)
1236     return;
1237
1238   selection_start_ = start;
1239   selection_end_ = end;
1240   SetNeedsCommit();
1241 }
1242
1243 int LayerTreeHost::ScheduleMicroBenchmark(
1244     const std::string& benchmark_name,
1245     scoped_ptr<base::Value> value,
1246     const MicroBenchmark::DoneCallback& callback) {
1247   return micro_benchmark_controller_.ScheduleRun(
1248       benchmark_name, value.Pass(), callback);
1249 }
1250
1251 bool LayerTreeHost::SendMessageToMicroBenchmark(int id,
1252                                                 scoped_ptr<base::Value> value) {
1253   return micro_benchmark_controller_.SendMessage(id, value.Pass());
1254 }
1255
1256 void LayerTreeHost::InsertSwapPromiseMonitor(SwapPromiseMonitor* monitor) {
1257   swap_promise_monitor_.insert(monitor);
1258 }
1259
1260 void LayerTreeHost::RemoveSwapPromiseMonitor(SwapPromiseMonitor* monitor) {
1261   swap_promise_monitor_.erase(monitor);
1262 }
1263
1264 void LayerTreeHost::NotifySwapPromiseMonitorsOfSetNeedsCommit() {
1265   std::set<SwapPromiseMonitor*>::iterator it = swap_promise_monitor_.begin();
1266   for (; it != swap_promise_monitor_.end(); it++)
1267     (*it)->OnSetNeedsCommitOnMain();
1268 }
1269
1270 void LayerTreeHost::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {
1271   DCHECK(swap_promise);
1272   if (swap_promise_list_.size() > kMaxQueuedSwapPromiseNumber)
1273     BreakSwapPromises(SwapPromise::SWAP_PROMISE_LIST_OVERFLOW);
1274   swap_promise_list_.push_back(swap_promise.Pass());
1275 }
1276
1277 void LayerTreeHost::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
1278   for (size_t i = 0; i < swap_promise_list_.size(); i++)
1279     swap_promise_list_[i]->DidNotSwap(reason);
1280   swap_promise_list_.clear();
1281 }
1282
1283 }  // namespace cc