cc/trees/layer_tree_host_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_host_impl.h"
   6
   7 #include <algorithm>
   8 #include <limits>
   9
  10 #include "base/basictypes.h"
  11 #include "base/containers/hash_tables.h"
  12 #include "base/debug/trace_event_argument.h"
  13 #include "base/json/json_writer.h"
  14 #include "base/metrics/histogram.h"
  15 #include "base/stl_util.h"
  16 #include "base/strings/stringprintf.h"
  17 #include "cc/animation/animation_id_provider.h"
  18 #include "cc/animation/scroll_offset_animation_curve.h"
  19 #include "cc/animation/scrollbar_animation_controller.h"
  20 #include "cc/animation/timing_function.h"
  21 #include "cc/base/latency_info_swap_promise_monitor.h"
  22 #include "cc/base/math_util.h"
  23 #include "cc/base/util.h"
  24 #include "cc/debug/benchmark_instrumentation.h"
  25 #include "cc/debug/debug_rect_history.h"
  26 #include "cc/debug/devtools_instrumentation.h"
  27 #include "cc/debug/frame_rate_counter.h"
  28 #include "cc/debug/paint_time_counter.h"
  29 #include "cc/debug/rendering_stats_instrumentation.h"
  30 #include "cc/debug/traced_value.h"
  31 #include "cc/input/page_scale_animation.h"
  32 #include "cc/input/top_controls_manager.h"
  33 #include "cc/layers/append_quads_data.h"
  34 #include "cc/layers/heads_up_display_layer_impl.h"
  35 #include "cc/layers/layer_impl.h"
  36 #include "cc/layers/layer_iterator.h"
  37 #include "cc/layers/painted_scrollbar_layer_impl.h"
  38 #include "cc/layers/render_surface_impl.h"
  39 #include "cc/layers/scrollbar_layer_impl_base.h"
  40 #include "cc/output/compositor_frame_metadata.h"
  41 #include "cc/output/copy_output_request.h"
  42 #include "cc/output/delegating_renderer.h"
  43 #include "cc/output/gl_renderer.h"
  44 #include "cc/output/software_renderer.h"
  45 #include "cc/quads/render_pass_draw_quad.h"
  46 #include "cc/quads/shared_quad_state.h"
  47 #include "cc/quads/solid_color_draw_quad.h"
  48 #include "cc/quads/texture_draw_quad.h"
  49 #include "cc/resources/bitmap_raster_worker_pool.h"
  50 #include "cc/resources/eviction_tile_priority_queue.h"
  51 #include "cc/resources/gpu_raster_worker_pool.h"
  52 #include "cc/resources/memory_history.h"
  53 #include "cc/resources/one_copy_raster_worker_pool.h"
  54 #include "cc/resources/picture_layer_tiling.h"
  55 #include "cc/resources/pixel_buffer_raster_worker_pool.h"
  56 #include "cc/resources/prioritized_resource_manager.h"
  57 #include "cc/resources/raster_tile_priority_queue.h"
  58 #include "cc/resources/raster_worker_pool.h"
  59 #include "cc/resources/resource_pool.h"
  60 #include "cc/resources/texture_mailbox_deleter.h"
  61 #include "cc/resources/ui_resource_bitmap.h"
  62 #include "cc/resources/zero_copy_raster_worker_pool.h"
  63 #include "cc/scheduler/delay_based_time_source.h"
  64 #include "cc/trees/damage_tracker.h"
  65 #include "cc/trees/layer_tree_host.h"
  66 #include "cc/trees/layer_tree_host_common.h"
  67 #include "cc/trees/layer_tree_impl.h"
  68 #include "cc/trees/occlusion_tracker.h"
  69 #include "cc/trees/single_thread_proxy.h"
  70 #include "cc/trees/tree_synchronizer.h"
  71 #include "gpu/command_buffer/client/gles2_interface.h"
  72 #include "gpu/GLES2/gl2extchromium.h"
  73 #include "ui/gfx/frame_time.h"
  74 #include "ui/gfx/geometry/rect_conversions.h"
  75 #include "ui/gfx/geometry/size_conversions.h"
  76 #include "ui/gfx/geometry/vector2d_conversions.h"
  77
  78 namespace cc {
  79 namespace {
  80
  81 // Small helper class that saves the current viewport location as the user sees
  82 // it and resets to the same location.
  83 class ViewportAnchor {
  84  public:
  85   ViewportAnchor(LayerImpl* inner_scroll, LayerImpl* outer_scroll)
  86   : inner_(inner_scroll),
  87     outer_(outer_scroll) {
  88     viewport_in_content_coordinates_ = inner_->TotalScrollOffset();
  89
  90     if (outer_)
  91       viewport_in_content_coordinates_ += outer_->TotalScrollOffset();
  92   }
  93
  94   void ResetViewportToAnchoredPosition() {
  95     DCHECK(outer_);
  96
  97     inner_->ClampScrollToMaxScrollOffset();
  98     outer_->ClampScrollToMaxScrollOffset();
  99
 100     gfx::ScrollOffset viewport_location = inner_->TotalScrollOffset() +
 101                                           outer_->TotalScrollOffset();
 102
 103     gfx::Vector2dF delta =
 104         viewport_in_content_coordinates_.DeltaFrom(viewport_location);
 105
 106     delta = outer_->ScrollBy(delta);
 107     inner_->ScrollBy(delta);
 108   }
 109
 110  private:
 111   LayerImpl* inner_;
 112   LayerImpl* outer_;
 113   gfx::ScrollOffset viewport_in_content_coordinates_;
 114 };
 115
 116
 117 void DidVisibilityChange(LayerTreeHostImpl* id, bool visible) {
 118   if (visible) {
 119     TRACE_EVENT_ASYNC_BEGIN1("webkit",
 120                              "LayerTreeHostImpl::SetVisible",
 121                              id,
 122                              "LayerTreeHostImpl",
 123                              id);
 124     return;
 125   }
 126
 127   TRACE_EVENT_ASYNC_END0("webkit", "LayerTreeHostImpl::SetVisible", id);
 128 }
 129
 130 size_t GetMaxTransferBufferUsageBytes(
 131     const ContextProvider::Capabilities& context_capabilities,
 132     double refresh_rate) {
 133   // We want to make sure the default transfer buffer size is equal to the
 134   // amount of data that can be uploaded by the compositor to avoid stalling
 135   // the pipeline.
 136   // For reference Chromebook Pixel can upload 1MB in about 0.5ms.
 137   const size_t kMaxBytesUploadedPerMs = 1024 * 1024 * 2;
 138
 139   // We need to upload at least enough work to keep the GPU process busy until
 140   // the next time it can handle a request to start more uploads from the
 141   // compositor. We assume that it will pick up any sent upload requests within
 142   // the time of a vsync, since the browser will want to swap a frame within
 143   // that time interval, and then uploads should have a chance to be processed.
 144   size_t ms_per_frame = std::floor(1000.0 / refresh_rate);
 145   size_t max_transfer_buffer_usage_bytes =
 146       ms_per_frame * kMaxBytesUploadedPerMs;
 147
 148   // The context may request a lower limit based on the device capabilities.
 149   return std::min(context_capabilities.max_transfer_buffer_usage_bytes,
 150                   max_transfer_buffer_usage_bytes);
 151 }
 152
 153 unsigned GetMapImageTextureTarget(
 154     const ContextProvider::Capabilities& context_capabilities) {
 155   if (context_capabilities.gpu.egl_image_external)
 156     return GL_TEXTURE_EXTERNAL_OES;
 157   if (context_capabilities.gpu.texture_rectangle)
 158     return GL_TEXTURE_RECTANGLE_ARB;
 159
 160   return GL_TEXTURE_2D;
 161 }
 162
 163 size_t GetMaxStagingResourceCount() {
 164   // Upper bound for number of staging resource to allow.
 165   return 32;
 166 }
 167
 168 }  // namespace
 169
 170 class LayerTreeHostImplTimeSourceAdapter : public TimeSourceClient {
 171  public:
 172   static scoped_ptr<LayerTreeHostImplTimeSourceAdapter> Create(
 173       LayerTreeHostImpl* layer_tree_host_impl,
 174       scoped_refptr<DelayBasedTimeSource> time_source) {
 175     return make_scoped_ptr(
 176         new LayerTreeHostImplTimeSourceAdapter(layer_tree_host_impl,
 177                                                time_source));
 178   }
 179   ~LayerTreeHostImplTimeSourceAdapter() override {
 180     time_source_->SetClient(NULL);
 181     time_source_->SetActive(false);
 182   }
 183
 184   void OnTimerTick() override {
 185     // In single threaded mode we attempt to simulate changing the current
 186     // thread by maintaining a fake thread id. When we switch from one
 187     // thread to another, we construct DebugScopedSetXXXThread objects that
 188     // update the thread id. This lets DCHECKS that ensure we're on the
 189     // right thread to work correctly in single threaded mode. The problem
 190     // here is that the timer tasks are run via the message loop, and when
 191     // they run, we've had no chance to construct a DebugScopedSetXXXThread
 192     // object. The result is that we report that we're running on the main
 193     // thread. In multi-threaded mode, this timer is run on the compositor
 194     // thread, so to keep this consistent in single-threaded mode, we'll
 195     // construct a DebugScopedSetImplThread object. There is no need to do
 196     // this in multi-threaded mode since the real thread id's will be
 197     // correct. In fact, setting fake thread id's interferes with the real
 198     // thread id's and causes breakage.
 199     scoped_ptr<DebugScopedSetImplThread> set_impl_thread;
 200     if (!layer_tree_host_impl_->proxy()->HasImplThread()) {
 201       set_impl_thread.reset(
 202           new DebugScopedSetImplThread(layer_tree_host_impl_->proxy()));
 203     }
 204
 205     layer_tree_host_impl_->Animate(
 206         layer_tree_host_impl_->CurrentBeginFrameArgs().frame_time);
 207     layer_tree_host_impl_->UpdateBackgroundAnimateTicking(true);
 208     bool start_ready_animations = true;
 209     layer_tree_host_impl_->UpdateAnimationState(start_ready_animations);
 210
 211     if (layer_tree_host_impl_->pending_tree()) {
 212       layer_tree_host_impl_->pending_tree()->UpdateDrawProperties();
 213       layer_tree_host_impl_->ManageTiles();
 214     }
 215
 216     layer_tree_host_impl_->ResetCurrentBeginFrameArgsForNextFrame();
 217   }
 218
 219   void SetActive(bool active) {
 220     if (active != time_source_->Active())
 221       time_source_->SetActive(active);
 222   }
 223
 224   bool Active() const { return time_source_->Active(); }
 225
 226  private:
 227   LayerTreeHostImplTimeSourceAdapter(
 228       LayerTreeHostImpl* layer_tree_host_impl,
 229       scoped_refptr<DelayBasedTimeSource> time_source)
 230       : layer_tree_host_impl_(layer_tree_host_impl),
 231         time_source_(time_source) {
 232     time_source_->SetClient(this);
 233   }
 234
 235   LayerTreeHostImpl* layer_tree_host_impl_;
 236   scoped_refptr<DelayBasedTimeSource> time_source_;
 237
 238   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImplTimeSourceAdapter);
 239 };
 240
 241 LayerTreeHostImpl::FrameData::FrameData()
 242     : contains_incomplete_tile(false), has_no_damage(false) {}
 243
 244 LayerTreeHostImpl::FrameData::~FrameData() {}
 245
 246 scoped_ptr<LayerTreeHostImpl> LayerTreeHostImpl::Create(
 247     const LayerTreeSettings& settings,
 248     LayerTreeHostImplClient* client,
 249     Proxy* proxy,
 250     RenderingStatsInstrumentation* rendering_stats_instrumentation,
 251     SharedBitmapManager* shared_bitmap_manager,
 252     gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
 253     int id) {
 254   return make_scoped_ptr(new LayerTreeHostImpl(settings,
 255                                                client,
 256                                                proxy,
 257                                                rendering_stats_instrumentation,
 258                                                shared_bitmap_manager,
 259                                                gpu_memory_buffer_manager,
 260                                                id));
 261 }
 262
 263 LayerTreeHostImpl::LayerTreeHostImpl(
 264     const LayerTreeSettings& settings,
 265     LayerTreeHostImplClient* client,
 266     Proxy* proxy,
 267     RenderingStatsInstrumentation* rendering_stats_instrumentation,
 268     SharedBitmapManager* shared_bitmap_manager,
 269     gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
 270     int id)
 271     : BeginFrameSourceMixIn(),
 272       client_(client),
 273       proxy_(proxy),
 274       use_gpu_rasterization_(false),
 275       input_handler_client_(NULL),
 276       did_lock_scrolling_layer_(false),
 277       should_bubble_scrolls_(false),
 278       wheel_scrolling_(false),
 279       scroll_affects_scroll_handler_(false),
 280       scroll_layer_id_when_mouse_over_scrollbar_(0),
 281       tile_priorities_dirty_(false),
 282       root_layer_scroll_offset_delegate_(NULL),
 283       settings_(settings),
 284       visible_(true),
 285       cached_managed_memory_policy_(
 286           PrioritizedResourceManager::DefaultMemoryAllocationLimit(),
 287           gpu::MemoryAllocation::CUTOFF_ALLOW_EVERYTHING,
 288           ManagedMemoryPolicy::kDefaultNumResourcesLimit),
 289       pinch_gesture_active_(false),
 290       pinch_gesture_end_should_clear_scrolling_layer_(false),
 291       fps_counter_(FrameRateCounter::Create(proxy_->HasImplThread())),
 292       paint_time_counter_(PaintTimeCounter::Create()),
 293       memory_history_(MemoryHistory::Create()),
 294       debug_rect_history_(DebugRectHistory::Create()),
 295       texture_mailbox_deleter_(new TextureMailboxDeleter(
 296           proxy_->HasImplThread() ? proxy_->ImplThreadTaskRunner()
 297                                   : proxy_->MainThreadTaskRunner())),
 298       max_memory_needed_bytes_(0),
 299       zero_budget_(false),
 300       device_scale_factor_(1.f),
 301       overhang_ui_resource_id_(0),
 302       resourceless_software_draw_(false),
 303       begin_impl_frame_interval_(BeginFrameArgs::DefaultInterval()),
 304       animation_registrar_(AnimationRegistrar::Create()),
 305       rendering_stats_instrumentation_(rendering_stats_instrumentation),
 306       micro_benchmark_controller_(this),
 307       need_to_update_visible_tiles_before_draw_(false),
 308       shared_bitmap_manager_(shared_bitmap_manager),
 309       gpu_memory_buffer_manager_(gpu_memory_buffer_manager),
 310       id_(id),
 311       requires_high_res_to_draw_(false) {
 312   DCHECK(proxy_->IsImplThread());
 313   DidVisibilityChange(this, visible_);
 314   animation_registrar_->set_supports_scroll_animations(
 315       proxy_->SupportsImplScrolling());
 316
 317   SetDebugState(settings.initial_debug_state);
 318
 319   // LTHI always has an active tree.
 320   active_tree_ = LayerTreeImpl::create(this);
 321   TRACE_EVENT_OBJECT_CREATED_WITH_ID(
 322       TRACE_DISABLED_BY_DEFAULT("cc.debug"), "cc::LayerTreeHostImpl", id_);
 323
 324   if (settings.calculate_top_controls_position) {
 325     top_controls_manager_ =
 326         TopControlsManager::Create(this,
 327                                    settings.top_controls_height,
 328                                    settings.top_controls_show_threshold,
 329                                    settings.top_controls_hide_threshold);
 330
 331     // TODO(bokan): This is a quick fix. The browser should lock the top
 332     // controls to shown on creation but this appears not to work. Tracked
 333     // in crbug.com/417680.
 334     // Initialize with top controls showing.
 335     SetControlsTopOffset(0.f);
 336   }
 337 }
 338
 339 LayerTreeHostImpl::~LayerTreeHostImpl() {
 340   DCHECK(proxy_->IsImplThread());
 341   TRACE_EVENT0("cc", "LayerTreeHostImpl::~LayerTreeHostImpl()");
 342   TRACE_EVENT_OBJECT_DELETED_WITH_ID(
 343       TRACE_DISABLED_BY_DEFAULT("cc.debug"), "cc::LayerTreeHostImpl", id_);
 344
 345   if (input_handler_client_) {
 346     input_handler_client_->WillShutdown();
 347     input_handler_client_ = NULL;
 348   }
 349
 350   // The layer trees must be destroyed before the layer tree host. We've
 351   // made a contract with our animation controllers that the registrar
 352   // will outlive them, and we must make good.
 353   if (recycle_tree_)
 354     recycle_tree_->Shutdown();
 355   if (pending_tree_)
 356     pending_tree_->Shutdown();
 357   active_tree_->Shutdown();
 358   recycle_tree_ = nullptr;
 359   pending_tree_ = nullptr;
 360   active_tree_ = nullptr;
 361   DestroyTileManager();
 362 }
 363
 364 void LayerTreeHostImpl::BeginMainFrameAborted(bool did_handle) {
 365   // If the begin frame data was handled, then scroll and scale set was applied
 366   // by the main thread, so the active tree needs to be updated as if these sent
 367   // values were applied and committed.
 368   if (did_handle) {
 369     active_tree_->ApplySentScrollAndScaleDeltasFromAbortedCommit();
 370     active_tree_->ResetContentsTexturesPurged();
 371   }
 372 }
 373
 374 void LayerTreeHostImpl::BeginCommit() {
 375   TRACE_EVENT0("cc", "LayerTreeHostImpl::BeginCommit");
 376
 377   if (UsePendingTreeForSync())
 378     CreatePendingTree();
 379 }
 380
 381 void LayerTreeHostImpl::CommitComplete() {
 382   TRACE_EVENT0("cc", "LayerTreeHostImpl::CommitComplete");
 383
 384   if (pending_tree_)
 385     pending_tree_->ApplyScrollDeltasSinceBeginMainFrame();
 386   sync_tree()->set_needs_update_draw_properties();
 387
 388   if (settings_.impl_side_painting) {
 389     // Impl-side painting needs an update immediately post-commit to have the
 390     // opportunity to create tilings.  Other paths can call UpdateDrawProperties
 391     // more lazily when needed prior to drawing.
 392     sync_tree()->UpdateDrawProperties();
 393     // Start working on newly created tiles immediately if needed.
 394     if (tile_manager_ && tile_priorities_dirty_)
 395       ManageTiles();
 396     else
 397       NotifyReadyToActivate();
 398   } else {
 399     // If we're not in impl-side painting, the tree is immediately considered
 400     // active.
 401     ActivateSyncTree();
 402   }
 403
 404   micro_benchmark_controller_.DidCompleteCommit();
 405 }
 406
 407 bool LayerTreeHostImpl::CanDraw() const {
 408   // Note: If you are changing this function or any other function that might
 409   // affect the result of CanDraw, make sure to call
 410   // client_->OnCanDrawStateChanged in the proper places and update the
 411   // NotifyIfCanDrawChanged test.
 412
 413   if (!renderer_) {
 414     TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::CanDraw no renderer",
 415                          TRACE_EVENT_SCOPE_THREAD);
 416     return false;
 417   }
 418
 419   // Must have an OutputSurface if |renderer_| is not NULL.
 420   DCHECK(output_surface_);
 421
 422   // TODO(boliu): Make draws without root_layer work and move this below
 423   // draw_and_swap_full_viewport_every_frame check. Tracked in crbug.com/264967.
 424   if (!active_tree_->root_layer()) {
 425     TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::CanDraw no root layer",
 426                          TRACE_EVENT_SCOPE_THREAD);
 427     return false;
 428   }
 429
 430   if (output_surface_->capabilities().draw_and_swap_full_viewport_every_frame)
 431     return true;
 432
 433   if (DrawViewportSize().IsEmpty()) {
 434     TRACE_EVENT_INSTANT0("cc", "LayerTreeHostImpl::CanDraw empty viewport",
 435                          TRACE_EVENT_SCOPE_THREAD);
 436     return false;
 437   }
 438   if (active_tree_->ViewportSizeInvalid()) {
 439     TRACE_EVENT_INSTANT0(
 440         "cc", "LayerTreeHostImpl::CanDraw viewport size recently changed",
 441         TRACE_EVENT_SCOPE_THREAD);
 442     return false;
 443   }
 444   if (active_tree_->ContentsTexturesPurged()) {
 445     TRACE_EVENT_INSTANT0(
 446         "cc", "LayerTreeHostImpl::CanDraw contents textures purged",
 447         TRACE_EVENT_SCOPE_THREAD);
 448     return false;
 449   }
 450   if (EvictedUIResourcesExist()) {
 451     TRACE_EVENT_INSTANT0(
 452         "cc", "LayerTreeHostImpl::CanDraw UI resources evicted not recreated",
 453         TRACE_EVENT_SCOPE_THREAD);
 454     return false;
 455   }
 456   return true;
 457 }
 458
 459 void LayerTreeHostImpl::Animate(base::TimeTicks monotonic_time) {
 460   if (input_handler_client_)
 461     input_handler_client_->Animate(monotonic_time);
 462   AnimatePageScale(monotonic_time);
 463   AnimateLayers(monotonic_time);
 464   AnimateScrollbars(monotonic_time);
 465   AnimateTopControls(monotonic_time);
 466 }
 467
 468 void LayerTreeHostImpl::ManageTiles() {
 469   if (!tile_manager_)
 470     return;
 471   if (!tile_priorities_dirty_)
 472     return;
 473
 474   tile_priorities_dirty_ = false;
 475   tile_manager_->ManageTiles(global_tile_state_);
 476
 477   client_->DidManageTiles();
 478 }
 479
 480 bool LayerTreeHostImpl::IsCurrentlyScrollingLayerAt(
 481     const gfx::Point& viewport_point,
 482     InputHandler::ScrollInputType type) {
 483   if (!CurrentlyScrollingLayer())
 484     return false;
 485
 486   gfx::PointF device_viewport_point =
 487       gfx::ScalePoint(viewport_point, device_scale_factor_);
 488
 489   LayerImpl* layer_impl =
 490       active_tree_->FindLayerThatIsHitByPoint(device_viewport_point);
 491
 492   bool scroll_on_main_thread = false;
 493   LayerImpl* scrolling_layer_impl = FindScrollLayerForDeviceViewportPoint(
 494       device_viewport_point, type, layer_impl, &scroll_on_main_thread, NULL);
 495   return CurrentlyScrollingLayer() == scrolling_layer_impl;
 496 }
 497
 498 bool LayerTreeHostImpl::HaveTouchEventHandlersAt(
 499     const gfx::Point& viewport_point) {
 500
 501   gfx::PointF device_viewport_point =
 502       gfx::ScalePoint(viewport_point, device_scale_factor_);
 503
 504   LayerImpl* layer_impl =
 505       active_tree_->FindLayerThatIsHitByPointInTouchHandlerRegion(
 506           device_viewport_point);
 507
 508   return layer_impl != NULL;
 509 }
 510
 511 scoped_ptr<SwapPromiseMonitor>
 512 LayerTreeHostImpl::CreateLatencyInfoSwapPromiseMonitor(
 513     ui::LatencyInfo* latency) {
 514   return make_scoped_ptr(
 515       new LatencyInfoSwapPromiseMonitor(latency, NULL, this));
 516 }
 517
 518 void LayerTreeHostImpl::QueueSwapPromiseForMainThreadScrollUpdate(
 519     scoped_ptr<SwapPromise> swap_promise) {
 520   swap_promises_for_main_thread_scroll_update_.push_back(swap_promise.Pass());
 521 }
 522
 523 void LayerTreeHostImpl::TrackDamageForAllSurfaces(
 524     LayerImpl* root_draw_layer,
 525     const LayerImplList& render_surface_layer_list) {
 526   // For now, we use damage tracking to compute a global scissor. To do this, we
 527   // must compute all damage tracking before drawing anything, so that we know
 528   // the root damage rect. The root damage rect is then used to scissor each
 529   // surface.
 530
 531   for (int surface_index = render_surface_layer_list.size() - 1;
 532        surface_index >= 0;
 533        --surface_index) {
 534     LayerImpl* render_surface_layer = render_surface_layer_list[surface_index];
 535     RenderSurfaceImpl* render_surface = render_surface_layer->render_surface();
 536     DCHECK(render_surface);
 537     render_surface->damage_tracker()->UpdateDamageTrackingState(
 538         render_surface->layer_list(),
 539         render_surface_layer->id(),
 540         render_surface->SurfacePropertyChangedOnlyFromDescendant(),
 541         render_surface->content_rect(),
 542         render_surface_layer->mask_layer(),
 543         render_surface_layer->filters());
 544   }
 545 }
 546
 547 void LayerTreeHostImpl::FrameData::AsValueInto(
 548     base::debug::TracedValue* value) const {
 549   value->SetBoolean("contains_incomplete_tile", contains_incomplete_tile);
 550   value->SetBoolean("has_no_damage", has_no_damage);
 551
 552   // Quad data can be quite large, so only dump render passes if we select
 553   // cc.debug.quads.
 554   bool quads_enabled;
 555   TRACE_EVENT_CATEGORY_GROUP_ENABLED(
 556       TRACE_DISABLED_BY_DEFAULT("cc.debug.quads"), &quads_enabled);
 557   if (quads_enabled) {
 558     value->BeginArray("render_passes");
 559     for (size_t i = 0; i < render_passes.size(); ++i) {
 560       value->BeginDictionary();
 561       render_passes[i]->AsValueInto(value);
 562       value->EndDictionary();
 563     }
 564     value->EndArray();
 565   }
 566 }
 567
 568 void LayerTreeHostImpl::FrameData::AppendRenderPass(
 569     scoped_ptr<RenderPass> render_pass) {
 570   render_passes_by_id[render_pass->id] = render_pass.get();
 571   render_passes.push_back(render_pass.Pass());
 572 }
 573
 574 DrawMode LayerTreeHostImpl::GetDrawMode() const {
 575   if (resourceless_software_draw_) {
 576     return DRAW_MODE_RESOURCELESS_SOFTWARE;
 577   } else if (output_surface_->context_provider()) {
 578     return DRAW_MODE_HARDWARE;
 579   } else {
 580     DCHECK_EQ(!output_surface_->software_device(),
 581               output_surface_->capabilities().delegated_rendering &&
 582                   !output_surface_->capabilities().deferred_gl_initialization)
 583         << output_surface_->capabilities().delegated_rendering << " "
 584         << output_surface_->capabilities().deferred_gl_initialization;
 585     return DRAW_MODE_SOFTWARE;
 586   }
 587 }
 588
 589 static void AppendQuadsForLayer(
 590     RenderPass* target_render_pass,
 591     LayerImpl* layer,
 592     const OcclusionTracker<LayerImpl>& occlusion_tracker,
 593     AppendQuadsData* append_quads_data) {
 594   layer->AppendQuads(
 595       target_render_pass,
 596       occlusion_tracker.GetCurrentOcclusionForLayer(layer->draw_transform()),
 597       append_quads_data);
 598 }
 599
 600 static void AppendQuadsForRenderSurfaceLayer(
 601     RenderPass* target_render_pass,
 602     LayerImpl* layer,
 603     const RenderPass* contributing_render_pass,
 604     const OcclusionTracker<LayerImpl>& occlusion_tracker,
 605     AppendQuadsData* append_quads_data) {
 606   bool is_replica = false;
 607   layer->render_surface()->AppendQuads(target_render_pass,
 608                                        occlusion_tracker,
 609                                        append_quads_data,
 610                                        is_replica,
 611                                        contributing_render_pass->id);
 612
 613   // Add replica after the surface so that it appears below the surface.
 614   if (layer->has_replica()) {
 615     is_replica = true;
 616     layer->render_surface()->AppendQuads(target_render_pass,
 617                                          occlusion_tracker,
 618                                          append_quads_data,
 619                                          is_replica,
 620                                          contributing_render_pass->id);
 621   }
 622 }
 623
 624 static void AppendQuadsToFillScreen(
 625     ResourceProvider::ResourceId overhang_resource_id,
 626     const gfx::SizeF& overhang_resource_scaled_size,
 627     const gfx::Rect& root_scroll_layer_rect,
 628     RenderPass* target_render_pass,
 629     LayerImpl* root_layer,
 630     SkColor screen_background_color,
 631     const OcclusionTracker<LayerImpl>& occlusion_tracker) {
 632   if (!root_layer || !SkColorGetA(screen_background_color))
 633     return;
 634
 635   Region fill_region = occlusion_tracker.ComputeVisibleRegionInScreen();
 636   if (fill_region.IsEmpty())
 637     return;
 638
 639   // Divide the fill region into the part to be filled with the overhang
 640   // resource and the part to be filled with the background color.
 641   Region screen_background_color_region = fill_region;
 642   Region overhang_region;
 643   if (overhang_resource_id) {
 644     overhang_region = fill_region;
 645     overhang_region.Subtract(root_scroll_layer_rect);
 646     screen_background_color_region.Intersect(root_scroll_layer_rect);
 647   }
 648
 649   // Manually create the quad state for the gutter quads, as the root layer
 650   // doesn't have any bounds and so can't generate this itself.
 651   // TODO(danakj): Make the gutter quads generated by the solid color layer
 652   // (make it smarter about generating quads to fill unoccluded areas).
 653
 654   gfx::Rect root_target_rect = root_layer->render_surface()->content_rect();
 655   float opacity = 1.f;
 656   int sorting_context_id = 0;
 657   SharedQuadState* shared_quad_state =
 658       target_render_pass->CreateAndAppendSharedQuadState();
 659   shared_quad_state->SetAll(gfx::Transform(),
 660                             root_target_rect.size(),
 661                             root_target_rect,
 662                             root_target_rect,
 663                             false,
 664                             opacity,
 665                             SkXfermode::kSrcOver_Mode,
 666                             sorting_context_id);
 667
 668   for (Region::Iterator fill_rects(screen_background_color_region);
 669        fill_rects.has_rect();
 670        fill_rects.next()) {
 671     gfx::Rect screen_space_rect = fill_rects.rect();
 672     gfx::Rect visible_screen_space_rect = screen_space_rect;
 673     // Skip the quad culler and just append the quads directly to avoid
 674     // occlusion checks.
 675     SolidColorDrawQuad* quad =
 676         target_render_pass->CreateAndAppendDrawQuad<SolidColorDrawQuad>();
 677     quad->SetNew(shared_quad_state,
 678                  screen_space_rect,
 679                  visible_screen_space_rect,
 680                  screen_background_color,
 681                  false);
 682   }
 683   for (Region::Iterator fill_rects(overhang_region);
 684        fill_rects.has_rect();
 685        fill_rects.next()) {
 686     DCHECK(overhang_resource_id);
 687     gfx::Rect screen_space_rect = fill_rects.rect();
 688     gfx::Rect opaque_screen_space_rect = screen_space_rect;
 689     gfx::Rect visible_screen_space_rect = screen_space_rect;
 690     TextureDrawQuad* tex_quad =
 691         target_render_pass->CreateAndAppendDrawQuad<TextureDrawQuad>();
 692     const float vertex_opacity[4] = {1.f, 1.f, 1.f, 1.f};
 693     tex_quad->SetNew(
 694         shared_quad_state,
 695         screen_space_rect,
 696         opaque_screen_space_rect,
 697         visible_screen_space_rect,
 698         overhang_resource_id,
 699         false,
 700         gfx::PointF(
 701             screen_space_rect.x() / overhang_resource_scaled_size.width(),
 702             screen_space_rect.y() / overhang_resource_scaled_size.height()),
 703         gfx::PointF(
 704             screen_space_rect.right() / overhang_resource_scaled_size.width(),
 705             screen_space_rect.bottom() /
 706                 overhang_resource_scaled_size.height()),
 707         screen_background_color,
 708         vertex_opacity,
 709         false);
 710   }
 711 }
 712
 713 DrawResult LayerTreeHostImpl::CalculateRenderPasses(
 714     FrameData* frame) {
 715   DCHECK(frame->render_passes.empty());
 716   DCHECK(CanDraw());
 717   DCHECK(active_tree_->root_layer());
 718
 719   TrackDamageForAllSurfaces(active_tree_->root_layer(),
 720                             *frame->render_surface_layer_list);
 721
 722   // If the root render surface has no visible damage, then don't generate a
 723   // frame at all.
 724   RenderSurfaceImpl* root_surface =
 725       active_tree_->root_layer()->render_surface();
 726   bool root_surface_has_no_visible_damage =
 727       !root_surface->damage_tracker()->current_damage_rect().Intersects(
 728           root_surface->content_rect());
 729   bool root_surface_has_contributing_layers =
 730       !root_surface->layer_list().empty();
 731   bool hud_wants_to_draw_ = active_tree_->hud_layer() &&
 732                             active_tree_->hud_layer()->IsAnimatingHUDContents();
 733   if (root_surface_has_contributing_layers &&
 734       root_surface_has_no_visible_damage &&
 735       active_tree_->LayersWithCopyOutputRequest().empty() &&
 736       !hud_wants_to_draw_) {
 737     TRACE_EVENT0("cc",
 738                  "LayerTreeHostImpl::CalculateRenderPasses::EmptyDamageRect");
 739     frame->has_no_damage = true;
 740     DCHECK(!output_surface_->capabilities()
 741                .draw_and_swap_full_viewport_every_frame);
 742     return DRAW_SUCCESS;
 743   }
 744
 745   TRACE_EVENT1("cc",
 746                "LayerTreeHostImpl::CalculateRenderPasses",
 747                "render_surface_layer_list.size()",
 748                static_cast<uint64>(frame->render_surface_layer_list->size()));
 749
 750   // Create the render passes in dependency order.
 751   for (int surface_index = frame->render_surface_layer_list->size() - 1;
 752        surface_index >= 0;
 753        --surface_index) {
 754     LayerImpl* render_surface_layer =
 755         (*frame->render_surface_layer_list)[surface_index];
 756     RenderSurfaceImpl* render_surface = render_surface_layer->render_surface();
 757
 758     bool should_draw_into_render_pass =
 759         render_surface_layer->parent() == NULL ||
 760         render_surface->contributes_to_drawn_surface() ||
 761         render_surface_layer->HasCopyRequest();
 762     if (should_draw_into_render_pass)
 763       render_surface_layer->render_surface()->AppendRenderPasses(frame);
 764   }
 765
 766   // When we are displaying the HUD, change the root damage rect to cover the
 767   // entire root surface. This will disable partial-swap/scissor optimizations
 768   // that would prevent the HUD from updating, since the HUD does not cause
 769   // damage itself, to prevent it from messing with damage visualizations. Since
 770   // damage visualizations are done off the LayerImpls and RenderSurfaceImpls,
 771   // changing the RenderPass does not affect them.
 772   if (active_tree_->hud_layer()) {
 773     RenderPass* root_pass = frame->render_passes.back();
 774     root_pass->damage_rect = root_pass->output_rect;
 775   }
 776
 777   OcclusionTracker<LayerImpl> occlusion_tracker(
 778       active_tree_->root_layer()->render_surface()->content_rect());
 779   occlusion_tracker.set_minimum_tracking_size(
 780       settings_.minimum_occlusion_tracking_size);
 781
 782   if (debug_state_.show_occluding_rects) {
 783     occlusion_tracker.set_occluding_screen_space_rects_container(
 784         &frame->occluding_screen_space_rects);
 785   }
 786   if (debug_state_.show_non_occluding_rects) {
 787     occlusion_tracker.set_non_occluding_screen_space_rects_container(
 788         &frame->non_occluding_screen_space_rects);
 789   }
 790
 791   // Add quads to the Render passes in front-to-back order to allow for testing
 792   // occlusion and performing culling during the tree walk.
 793   typedef LayerIterator<LayerImpl> LayerIteratorType;
 794
 795   // Typically when we are missing a texture and use a checkerboard quad, we
 796   // still draw the frame. However when the layer being checkerboarded is moving
 797   // due to an impl-animation, we drop the frame to avoid flashing due to the
 798   // texture suddenly appearing in the future.
 799   DrawResult draw_result = DRAW_SUCCESS;
 800   // When we have a copy request for a layer, we need to draw no matter
 801   // what, as the layer may disappear after this frame.
 802   bool have_copy_request = false;
 803
 804   int layers_drawn = 0;
 805
 806   const DrawMode draw_mode = GetDrawMode();
 807
 808   int num_missing_tiles = 0;
 809   int num_incomplete_tiles = 0;
 810
 811   LayerIteratorType end =
 812       LayerIteratorType::End(frame->render_surface_layer_list);
 813   for (LayerIteratorType it =
 814            LayerIteratorType::Begin(frame->render_surface_layer_list);
 815        it != end;
 816        ++it) {
 817     RenderPassId target_render_pass_id =
 818         it.target_render_surface_layer()->render_surface()->GetRenderPassId();
 819     RenderPass* target_render_pass =
 820         frame->render_passes_by_id[target_render_pass_id];
 821
 822     occlusion_tracker.EnterLayer(it);
 823
 824     AppendQuadsData append_quads_data(target_render_pass_id);
 825
 826     if (it.represents_target_render_surface()) {
 827       if (it->HasCopyRequest()) {
 828         have_copy_request = true;
 829         it->TakeCopyRequestsAndTransformToTarget(
 830             &target_render_pass->copy_requests);
 831       }
 832     } else if (it.represents_contributing_render_surface() &&
 833                it->render_surface()->contributes_to_drawn_surface()) {
 834       RenderPassId contributing_render_pass_id =
 835           it->render_surface()->GetRenderPassId();
 836       RenderPass* contributing_render_pass =
 837           frame->render_passes_by_id[contributing_render_pass_id];
 838       AppendQuadsForRenderSurfaceLayer(target_render_pass,
 839                                        *it,
 840                                        contributing_render_pass,
 841                                        occlusion_tracker,
 842                                        &append_quads_data);
 843     } else if (it.represents_itself() &&
 844                !it->visible_content_rect().IsEmpty()) {
 845       bool occluded =
 846           occlusion_tracker.GetCurrentOcclusionForLayer(it->draw_transform())
 847               .IsOccluded(it->visible_content_rect());
 848       if (!occluded && it->WillDraw(draw_mode, resource_provider_.get())) {
 849         DCHECK_EQ(active_tree_, it->layer_tree_impl());
 850
 851         frame->will_draw_layers.push_back(*it);
 852
 853         if (it->HasContributingDelegatedRenderPasses()) {
 854           RenderPassId contributing_render_pass_id =
 855               it->FirstContributingRenderPassId();
 856           while (frame->render_passes_by_id.find(contributing_render_pass_id) !=
 857                  frame->render_passes_by_id.end()) {
 858             RenderPass* render_pass =
 859                 frame->render_passes_by_id[contributing_render_pass_id];
 860
 861             AppendQuadsData append_quads_data(render_pass->id);
 862             AppendQuadsForLayer(render_pass,
 863                                 *it,
 864                                 occlusion_tracker,
 865                                 &append_quads_data);
 866
 867             contributing_render_pass_id =
 868                 it->NextContributingRenderPassId(contributing_render_pass_id);
 869           }
 870         }
 871
 872         AppendQuadsForLayer(target_render_pass,
 873                             *it,
 874                             occlusion_tracker,
 875                             &append_quads_data);
 876       }
 877
 878       ++layers_drawn;
 879     }
 880
 881     rendering_stats_instrumentation_->AddVisibleContentArea(
 882         append_quads_data.visible_content_area);
 883     rendering_stats_instrumentation_->AddApproximatedVisibleContentArea(
 884         append_quads_data.approximated_visible_content_area);
 885
 886     num_missing_tiles += append_quads_data.num_missing_tiles;
 887     num_incomplete_tiles += append_quads_data.num_incomplete_tiles;
 888
 889     if (append_quads_data.num_missing_tiles) {
 890       bool layer_has_animating_transform =
 891           it->screen_space_transform_is_animating() ||
 892           it->draw_transform_is_animating();
 893       if (layer_has_animating_transform)
 894         draw_result = DRAW_ABORTED_CHECKERBOARD_ANIMATIONS;
 895     }
 896
 897     if (append_quads_data.num_incomplete_tiles ||
 898         append_quads_data.num_missing_tiles) {
 899       frame->contains_incomplete_tile = true;
 900       if (RequiresHighResToDraw())
 901         draw_result = DRAW_ABORTED_MISSING_HIGH_RES_CONTENT;
 902     }
 903
 904     occlusion_tracker.LeaveLayer(it);
 905   }
 906
 907   if (have_copy_request ||
 908       output_surface_->capabilities().draw_and_swap_full_viewport_every_frame)
 909     draw_result = DRAW_SUCCESS;
 910
 911 #if DCHECK_IS_ON
 912   for (const auto& render_pass : frame->render_passes) {
 913     for (const auto& quad : render_pass->quad_list)
 914       DCHECK(quad->shared_quad_state);
 915     DCHECK(frame->render_passes_by_id.find(render_pass->id) !=
 916            frame->render_passes_by_id.end());
 917   }
 918 #endif
 919   DCHECK(frame->render_passes.back()->output_rect.origin().IsOrigin());
 920
 921   if (!active_tree_->has_transparent_background()) {
 922     frame->render_passes.back()->has_transparent_background = false;
 923     AppendQuadsToFillScreen(
 924         ResourceIdForUIResource(overhang_ui_resource_id_),
 925         gfx::ScaleSize(overhang_ui_resource_size_, device_scale_factor_),
 926         active_tree_->RootScrollLayerDeviceViewportBounds(),
 927         frame->render_passes.back(),
 928         active_tree_->root_layer(),
 929         active_tree_->background_color(),
 930         occlusion_tracker);
 931   }
 932
 933   RemoveRenderPasses(CullRenderPassesWithNoQuads(), frame);
 934   renderer_->DecideRenderPassAllocationsForFrame(frame->render_passes);
 935
 936   // Any copy requests left in the tree are not going to get serviced, and
 937   // should be aborted.
 938   ScopedPtrVector<CopyOutputRequest> requests_to_abort;
 939   while (!active_tree_->LayersWithCopyOutputRequest().empty()) {
 940     LayerImpl* layer = active_tree_->LayersWithCopyOutputRequest().back();
 941     layer->TakeCopyRequestsAndTransformToTarget(&requests_to_abort);
 942   }
 943   for (size_t i = 0; i < requests_to_abort.size(); ++i)
 944     requests_to_abort[i]->SendEmptyResult();
 945
 946   // If we're making a frame to draw, it better have at least one render pass.
 947   DCHECK(!frame->render_passes.empty());
 948
 949   if (active_tree_->has_ever_been_drawn()) {
 950     UMA_HISTOGRAM_COUNTS_100(
 951         "Compositing.RenderPass.AppendQuadData.NumMissingTiles",
 952         num_missing_tiles);
 953     UMA_HISTOGRAM_COUNTS_100(
 954         "Compositing.RenderPass.AppendQuadData.NumIncompleteTiles",
 955         num_incomplete_tiles);
 956   }
 957
 958   // Should only have one render pass in resourceless software mode.
 959   DCHECK(draw_mode != DRAW_MODE_RESOURCELESS_SOFTWARE ||
 960          frame->render_passes.size() == 1u)
 961       << frame->render_passes.size();
 962
 963   return draw_result;
 964 }
 965
 966 void LayerTreeHostImpl::MainThreadHasStoppedFlinging() {
 967   if (input_handler_client_)
 968     input_handler_client_->MainThreadHasStoppedFlinging();
 969 }
 970
 971 void LayerTreeHostImpl::UpdateBackgroundAnimateTicking(
 972     bool should_background_tick) {
 973   DCHECK(proxy_->IsImplThread());
 974   if (should_background_tick)
 975     DCHECK(active_tree_->root_layer());
 976
 977   bool enabled = should_background_tick && needs_animate_layers();
 978
 979   // Lazily create the time_source adapter so that we can vary the interval for
 980   // testing.
 981   if (!time_source_client_adapter_) {
 982     time_source_client_adapter_ = LayerTreeHostImplTimeSourceAdapter::Create(
 983         this,
 984         DelayBasedTimeSource::Create(
 985             LowFrequencyAnimationInterval(),
 986             proxy_->HasImplThread() ? proxy_->ImplThreadTaskRunner()
 987                                     : proxy_->MainThreadTaskRunner()));
 988   }
 989
 990   time_source_client_adapter_->SetActive(enabled);
 991 }
 992
 993 void LayerTreeHostImpl::DidAnimateScrollOffset() {
 994   client_->SetNeedsCommitOnImplThread();
 995   client_->RenewTreePriority();
 996 }
 997
 998 void LayerTreeHostImpl::SetViewportDamage(const gfx::Rect& damage_rect) {
 999   viewport_damage_rect_.Union(damage_rect);
1000 }
1001
1002 static inline RenderPass* FindRenderPassById(
1003     RenderPassId render_pass_id,
1004     const LayerTreeHostImpl::FrameData& frame) {
1005   RenderPassIdHashMap::const_iterator it =
1006       frame.render_passes_by_id.find(render_pass_id);
1007   return it != frame.render_passes_by_id.end() ? it->second : NULL;
1008 }
1009
1010 static void RemoveRenderPassesRecursive(RenderPassId remove_render_pass_id,
1011                                         LayerTreeHostImpl::FrameData* frame) {
1012   RenderPass* remove_render_pass =
1013       FindRenderPassById(remove_render_pass_id, *frame);
1014   // The pass was already removed by another quad - probably the original, and
1015   // we are the replica.
1016   if (!remove_render_pass)
1017     return;
1018   RenderPassList& render_passes = frame->render_passes;
1019   RenderPassList::iterator to_remove = std::find(render_passes.begin(),
1020                                                  render_passes.end(),
1021                                                  remove_render_pass);
1022
1023   DCHECK(to_remove != render_passes.end());
1024
1025   scoped_ptr<RenderPass> removed_pass = render_passes.take(to_remove);
1026   frame->render_passes.erase(to_remove);
1027   frame->render_passes_by_id.erase(remove_render_pass_id);
1028
1029   // Now follow up for all RenderPass quads and remove their RenderPasses
1030   // recursively.
1031   const QuadList& quad_list = removed_pass->quad_list;
1032   for (auto quad_list_iterator = quad_list.BackToFrontBegin();
1033        quad_list_iterator != quad_list.BackToFrontEnd();
1034        ++quad_list_iterator) {
1035     const DrawQuad* current_quad = *quad_list_iterator;
1036     if (current_quad->material != DrawQuad::RENDER_PASS)
1037       continue;
1038
1039     RenderPassId next_remove_render_pass_id =
1040         RenderPassDrawQuad::MaterialCast(current_quad)->render_pass_id;
1041     RemoveRenderPassesRecursive(next_remove_render_pass_id, frame);
1042   }
1043 }
1044
1045 bool LayerTreeHostImpl::CullRenderPassesWithNoQuads::ShouldRemoveRenderPass(
1046     const RenderPassDrawQuad& quad, const FrameData& frame) const {
1047   const RenderPass* render_pass =
1048       FindRenderPassById(quad.render_pass_id, frame);
1049   if (!render_pass)
1050     return false;
1051
1052   // If any quad or RenderPass draws into this RenderPass, then keep it.
1053   const QuadList& quad_list = render_pass->quad_list;
1054   for (auto quad_list_iterator = quad_list.BackToFrontBegin();
1055        quad_list_iterator != quad_list.BackToFrontEnd();
1056        ++quad_list_iterator) {
1057     const DrawQuad* current_quad = *quad_list_iterator;
1058
1059     if (current_quad->material != DrawQuad::RENDER_PASS)
1060       return false;
1061
1062     const RenderPass* contributing_pass = FindRenderPassById(
1063         RenderPassDrawQuad::MaterialCast(current_quad)->render_pass_id, frame);
1064     if (contributing_pass)
1065       return false;
1066   }
1067   return true;
1068 }
1069
1070 // Defined for linking tests.
1071 template CC_EXPORT void LayerTreeHostImpl::RemoveRenderPasses<
1072   LayerTreeHostImpl::CullRenderPassesWithNoQuads>(
1073       CullRenderPassesWithNoQuads culler, FrameData*);
1074
1075 // static
1076 template <typename RenderPassCuller>
1077 void LayerTreeHostImpl::RemoveRenderPasses(RenderPassCuller culler,
1078                                            FrameData* frame) {
1079   for (size_t it = culler.RenderPassListBegin(frame->render_passes);
1080        it != culler.RenderPassListEnd(frame->render_passes);
1081        it = culler.RenderPassListNext(it)) {
1082     const RenderPass* current_pass = frame->render_passes[it];
1083     const QuadList& quad_list = current_pass->quad_list;
1084
1085     for (auto quad_list_iterator = quad_list.BackToFrontBegin();
1086          quad_list_iterator != quad_list.BackToFrontEnd();
1087          ++quad_list_iterator) {
1088       const DrawQuad* current_quad = *quad_list_iterator;
1089
1090       if (current_quad->material != DrawQuad::RENDER_PASS)
1091         continue;
1092
1093       const RenderPassDrawQuad* render_pass_quad =
1094           RenderPassDrawQuad::MaterialCast(current_quad);
1095       if (!culler.ShouldRemoveRenderPass(*render_pass_quad, *frame))
1096         continue;
1097
1098       // We are changing the vector in the middle of iteration. Because we
1099       // delete render passes that draw into the current pass, we are
1100       // guaranteed that any data from the iterator to the end will not
1101       // change. So, capture the iterator position from the end of the
1102       // list, and restore it after the change.
1103       size_t position_from_end = frame->render_passes.size() - it;
1104       RemoveRenderPassesRecursive(render_pass_quad->render_pass_id, frame);
1105       it = frame->render_passes.size() - position_from_end;
1106       DCHECK_GE(frame->render_passes.size(), position_from_end);
1107     }
1108   }
1109 }
1110
1111 DrawResult LayerTreeHostImpl::PrepareToDraw(FrameData* frame) {
1112   TRACE_EVENT1("cc",
1113                "LayerTreeHostImpl::PrepareToDraw",
1114                "SourceFrameNumber",
1115                active_tree_->source_frame_number());
1116
1117   if (need_to_update_visible_tiles_before_draw_ &&
1118       tile_manager_ && tile_manager_->UpdateVisibleTiles()) {
1119     DidInitializeVisibleTile();
1120   }
1121   need_to_update_visible_tiles_before_draw_ = true;
1122
1123   UMA_HISTOGRAM_CUSTOM_COUNTS(
1124       "Compositing.NumActiveLayers", active_tree_->NumLayers(), 1, 400, 20);
1125
1126   bool ok = active_tree_->UpdateDrawProperties();
1127   DCHECK(ok) << "UpdateDrawProperties failed during draw";
1128
1129   frame->render_surface_layer_list = &active_tree_->RenderSurfaceLayerList();
1130   frame->render_passes.clear();
1131   frame->render_passes_by_id.clear();
1132   frame->will_draw_layers.clear();
1133   frame->contains_incomplete_tile = false;
1134   frame->has_no_damage = false;
1135
1136   if (active_tree_->root_layer()) {
1137     gfx::Rect device_viewport_damage_rect = viewport_damage_rect_;
1138     viewport_damage_rect_ = gfx::Rect();
1139
1140     active_tree_->root_layer()->render_surface()->damage_tracker()->
1141         AddDamageNextUpdate(device_viewport_damage_rect);
1142   }
1143
1144   DrawResult draw_result = CalculateRenderPasses(frame);
1145   if (draw_result != DRAW_SUCCESS) {
1146     DCHECK(!output_surface_->capabilities()
1147                .draw_and_swap_full_viewport_every_frame);
1148     return draw_result;
1149   }
1150
1151   // If we return DRAW_SUCCESS, then we expect DrawLayers() to be called before
1152   // this function is called again.
1153   return draw_result;
1154 }
1155
1156 void LayerTreeHostImpl::EvictTexturesForTesting() {
1157   EnforceManagedMemoryPolicy(ManagedMemoryPolicy(0));
1158 }
1159
1160 void LayerTreeHostImpl::BlockNotifyReadyToActivateForTesting(bool block) {
1161   NOTREACHED();
1162 }
1163
1164 void LayerTreeHostImpl::DidInitializeVisibleTileForTesting() {
1165   // Add arbitrary damage, to trigger prepare-to-draws.
1166   // Here, setting damage as viewport size, used only for testing.
1167   SetFullRootLayerDamage();
1168   DidInitializeVisibleTile();
1169 }
1170
1171 void LayerTreeHostImpl::ResetTreesForTesting() {
1172   if (active_tree_)
1173     active_tree_->DetachLayerTree();
1174   active_tree_ = LayerTreeImpl::create(this);
1175   if (pending_tree_)
1176     pending_tree_->DetachLayerTree();
1177   pending_tree_ = nullptr;
1178   if (recycle_tree_)
1179     recycle_tree_->DetachLayerTree();
1180   recycle_tree_ = nullptr;
1181 }
1182
1183 void LayerTreeHostImpl::EnforceManagedMemoryPolicy(
1184     const ManagedMemoryPolicy& policy) {
1185
1186   bool evicted_resources = client_->ReduceContentsTextureMemoryOnImplThread(
1187       visible_ ? policy.bytes_limit_when_visible : 0,
1188       ManagedMemoryPolicy::PriorityCutoffToValue(
1189           visible_ ? policy.priority_cutoff_when_visible
1190                    : gpu::MemoryAllocation::CUTOFF_ALLOW_NOTHING));
1191   if (evicted_resources) {
1192     active_tree_->SetContentsTexturesPurged();
1193     if (pending_tree_)
1194       pending_tree_->SetContentsTexturesPurged();
1195     client_->SetNeedsCommitOnImplThread();
1196     client_->OnCanDrawStateChanged(CanDraw());
1197     client_->RenewTreePriority();
1198   }
1199
1200   UpdateTileManagerMemoryPolicy(policy);
1201 }
1202
1203 void LayerTreeHostImpl::UpdateTileManagerMemoryPolicy(
1204     const ManagedMemoryPolicy& policy) {
1205   if (!tile_manager_)
1206     return;
1207
1208   global_tile_state_.hard_memory_limit_in_bytes = 0;
1209   global_tile_state_.soft_memory_limit_in_bytes = 0;
1210   if (visible_ && policy.bytes_limit_when_visible > 0) {
1211     global_tile_state_.hard_memory_limit_in_bytes =
1212         policy.bytes_limit_when_visible;
1213     global_tile_state_.soft_memory_limit_in_bytes =
1214         (static_cast<int64>(global_tile_state_.hard_memory_limit_in_bytes) *
1215          settings_.max_memory_for_prepaint_percentage) /
1216         100;
1217   }
1218   global_tile_state_.memory_limit_policy =
1219       ManagedMemoryPolicy::PriorityCutoffToTileMemoryLimitPolicy(
1220           visible_ ?
1221           policy.priority_cutoff_when_visible :
1222           gpu::MemoryAllocation::CUTOFF_ALLOW_NOTHING);
1223   global_tile_state_.num_resources_limit = policy.num_resources_limit;
1224
1225   // TODO(reveman): We should avoid keeping around unused resources if
1226   // possible. crbug.com/224475
1227   // Unused limit is calculated from soft-limit, as hard-limit may
1228   // be very high and shouldn't typically be exceeded.
1229   size_t unused_memory_limit_in_bytes = static_cast<size_t>(
1230       (static_cast<int64>(global_tile_state_.soft_memory_limit_in_bytes) *
1231        settings_.max_unused_resource_memory_percentage) /
1232       100);
1233
1234   DCHECK(resource_pool_);
1235   resource_pool_->CheckBusyResources(false);
1236   // Soft limit is used for resource pool such that memory returns to soft
1237   // limit after going over.
1238   resource_pool_->SetResourceUsageLimits(
1239       global_tile_state_.soft_memory_limit_in_bytes,
1240       unused_memory_limit_in_bytes,
1241       global_tile_state_.num_resources_limit);
1242
1243   // Release all staging resources when invisible.
1244   if (staging_resource_pool_) {
1245     staging_resource_pool_->CheckBusyResources(false);
1246     staging_resource_pool_->SetResourceUsageLimits(
1247         std::numeric_limits<size_t>::max(),
1248         std::numeric_limits<size_t>::max(),
1249         visible_ ? GetMaxStagingResourceCount() : 0);
1250   }
1251
1252   DidModifyTilePriorities();
1253 }
1254
1255 void LayerTreeHostImpl::DidModifyTilePriorities() {
1256   DCHECK(settings_.impl_side_painting);
1257   // Mark priorities as dirty and schedule a ManageTiles().
1258   tile_priorities_dirty_ = true;
1259   client_->SetNeedsManageTilesOnImplThread();
1260 }
1261
1262 void LayerTreeHostImpl::DidInitializeVisibleTile() {
1263   if (client_ && !client_->IsInsideDraw())
1264     client_->DidInitializeVisibleTileOnImplThread();
1265 }
1266
1267 void LayerTreeHostImpl::GetPictureLayerImplPairs(
1268     std::vector<PictureLayerImpl::Pair>* layer_pairs) const {
1269   DCHECK(layer_pairs->empty());
1270   for (std::vector<PictureLayerImpl*>::const_iterator it =
1271            picture_layers_.begin();
1272        it != picture_layers_.end();
1273        ++it) {
1274     PictureLayerImpl* layer = *it;
1275
1276     // TODO(vmpstr): Iterators and should handle this instead. crbug.com/381704
1277     if (!layer->HasValidTilePriorities())
1278       continue;
1279
1280     PictureLayerImpl* twin_layer = layer->GetPendingOrActiveTwinLayer();
1281
1282     // Ignore the twin layer when tile priorities are invalid.
1283     // TODO(vmpstr): Iterators should handle this instead. crbug.com/381704
1284     if (twin_layer && !twin_layer->HasValidTilePriorities())
1285       twin_layer = NULL;
1286
1287     // If the current tree is ACTIVE_TREE, then always generate a layer_pair.
1288     // If current tree is PENDING_TREE, then only generate a layer_pair if
1289     // there is no twin layer.
1290     if (layer->GetTree() == ACTIVE_TREE) {
1291       DCHECK(!twin_layer || twin_layer->GetTree() == PENDING_TREE);
1292       layer_pairs->push_back(PictureLayerImpl::Pair(layer, twin_layer));
1293     } else if (!twin_layer) {
1294       layer_pairs->push_back(PictureLayerImpl::Pair(NULL, layer));
1295     }
1296   }
1297 }
1298
1299 void LayerTreeHostImpl::BuildRasterQueue(RasterTilePriorityQueue* queue,
1300                                          TreePriority tree_priority) {
1301   TRACE_EVENT0("cc", "LayerTreeHostImpl::BuildRasterQueue");
1302   picture_layer_pairs_.clear();
1303   GetPictureLayerImplPairs(&picture_layer_pairs_);
1304   queue->Build(picture_layer_pairs_, tree_priority);
1305 }
1306
1307 void LayerTreeHostImpl::BuildEvictionQueue(EvictionTilePriorityQueue* queue,
1308                                            TreePriority tree_priority) {
1309   TRACE_EVENT0("cc", "LayerTreeHostImpl::BuildEvictionQueue");
1310   picture_layer_pairs_.clear();
1311   GetPictureLayerImplPairs(&picture_layer_pairs_);
1312   queue->Build(picture_layer_pairs_, tree_priority);
1313 }
1314
1315 const std::vector<PictureLayerImpl*>& LayerTreeHostImpl::GetPictureLayers()
1316     const {
1317   return picture_layers_;
1318 }
1319
1320 void LayerTreeHostImpl::NotifyReadyToActivate() {
1321   client_->NotifyReadyToActivate();
1322 }
1323
1324 void LayerTreeHostImpl::NotifyTileStateChanged(const Tile* tile) {
1325   TRACE_EVENT0("cc", "LayerTreeHostImpl::NotifyTileStateChanged");
1326
1327   if (active_tree_) {
1328     LayerImpl* layer_impl =
1329         active_tree_->FindActiveTreeLayerById(tile->layer_id());
1330     if (layer_impl)
1331       layer_impl->NotifyTileStateChanged(tile);
1332   }
1333
1334   if (pending_tree_) {
1335     LayerImpl* layer_impl =
1336         pending_tree_->FindPendingTreeLayerById(tile->layer_id());
1337     if (layer_impl)
1338       layer_impl->NotifyTileStateChanged(tile);
1339   }
1340 }
1341
1342 void LayerTreeHostImpl::SetMemoryPolicy(const ManagedMemoryPolicy& policy) {
1343   SetManagedMemoryPolicy(policy, zero_budget_);
1344 }
1345
1346 void LayerTreeHostImpl::SetTreeActivationCallback(
1347     const base::Closure& callback) {
1348   DCHECK(proxy_->IsImplThread());
1349   DCHECK(settings_.impl_side_painting || callback.is_null());
1350   tree_activation_callback_ = callback;
1351 }
1352
1353 void LayerTreeHostImpl::SetManagedMemoryPolicy(
1354     const ManagedMemoryPolicy& policy, bool zero_budget) {
1355   if (cached_managed_memory_policy_ == policy && zero_budget_ == zero_budget)
1356     return;
1357
1358   ManagedMemoryPolicy old_policy = ActualManagedMemoryPolicy();
1359
1360   cached_managed_memory_policy_ = policy;
1361   zero_budget_ = zero_budget;
1362   ManagedMemoryPolicy actual_policy = ActualManagedMemoryPolicy();
1363
1364   if (old_policy == actual_policy)
1365     return;
1366
1367   if (!proxy_->HasImplThread()) {
1368     // In single-thread mode, this can be called on the main thread by
1369     // GLRenderer::OnMemoryAllocationChanged.
1370     DebugScopedSetImplThread impl_thread(proxy_);
1371     EnforceManagedMemoryPolicy(actual_policy);
1372   } else {
1373     DCHECK(proxy_->IsImplThread());
1374     EnforceManagedMemoryPolicy(actual_policy);
1375   }
1376
1377   // If there is already enough memory to draw everything imaginable and the
1378   // new memory limit does not change this, then do not re-commit. Don't bother
1379   // skipping commits if this is not visible (commits don't happen when not
1380   // visible, there will almost always be a commit when this becomes visible).
1381   bool needs_commit = true;
1382   if (visible() &&
1383       actual_policy.bytes_limit_when_visible >= max_memory_needed_bytes_ &&
1384       old_policy.bytes_limit_when_visible >= max_memory_needed_bytes_ &&
1385       actual_policy.priority_cutoff_when_visible ==
1386           old_policy.priority_cutoff_when_visible) {
1387     needs_commit = false;
1388   }
1389
1390   if (needs_commit)
1391     client_->SetNeedsCommitOnImplThread();
1392 }
1393
1394 void LayerTreeHostImpl::SetExternalDrawConstraints(
1395     const gfx::Transform& transform,
1396     const gfx::Rect& viewport,
1397     const gfx::Rect& clip,
1398     const gfx::Rect& viewport_rect_for_tile_priority,
1399     const gfx::Transform& transform_for_tile_priority,
1400     bool resourceless_software_draw) {
1401   gfx::Rect viewport_rect_for_tile_priority_in_view_space;
1402   if (!resourceless_software_draw) {
1403     gfx::Transform screen_to_view(gfx::Transform::kSkipInitialization);
1404     if (transform_for_tile_priority.GetInverse(&screen_to_view)) {
1405       // Convert from screen space to view space.
1406       viewport_rect_for_tile_priority_in_view_space =
1407           gfx::ToEnclosingRect(MathUtil::ProjectClippedRect(
1408               screen_to_view, viewport_rect_for_tile_priority));
1409     }
1410   }
1411
1412   if (external_transform_ != transform || external_viewport_ != viewport ||
1413       resourceless_software_draw_ != resourceless_software_draw ||
1414       viewport_rect_for_tile_priority_ !=
1415           viewport_rect_for_tile_priority_in_view_space) {
1416     active_tree_->set_needs_update_draw_properties();
1417   }
1418
1419   external_transform_ = transform;
1420   external_viewport_ = viewport;
1421   external_clip_ = clip;
1422   viewport_rect_for_tile_priority_ =
1423       viewport_rect_for_tile_priority_in_view_space;
1424   resourceless_software_draw_ = resourceless_software_draw;
1425 }
1426
1427 void LayerTreeHostImpl::SetNeedsRedrawRect(const gfx::Rect& damage_rect) {
1428   if (damage_rect.IsEmpty())
1429     return;
1430   NotifySwapPromiseMonitorsOfSetNeedsRedraw();
1431   client_->SetNeedsRedrawRectOnImplThread(damage_rect);
1432 }
1433
1434 void LayerTreeHostImpl::BeginFrame(const BeginFrameArgs& args) {
1435   CallOnBeginFrame(args);
1436 }
1437
1438 void LayerTreeHostImpl::DidSwapBuffers() {
1439   client_->DidSwapBuffersOnImplThread();
1440 }
1441
1442 void LayerTreeHostImpl::DidSwapBuffersComplete() {
1443   client_->DidSwapBuffersCompleteOnImplThread();
1444 }
1445
1446 void LayerTreeHostImpl::ReclaimResources(const CompositorFrameAck* ack) {
1447   // TODO(piman): We may need to do some validation on this ack before
1448   // processing it.
1449   if (renderer_)
1450     renderer_->ReceiveSwapBuffersAck(*ack);
1451
1452   // In OOM, we now might be able to release more resources that were held
1453   // because they were exported.
1454   if (tile_manager_) {
1455     DCHECK(resource_pool_);
1456
1457     resource_pool_->CheckBusyResources(false);
1458     resource_pool_->ReduceResourceUsage();
1459   }
1460   // If we're not visible, we likely released resources, so we want to
1461   // aggressively flush here to make sure those DeleteTextures make it to the
1462   // GPU process to free up the memory.
1463   if (output_surface_->context_provider() && !visible_) {
1464     output_surface_->context_provider()->ContextGL()->ShallowFlushCHROMIUM();
1465   }
1466 }
1467
1468 void LayerTreeHostImpl::OnCanDrawStateChangedForTree() {
1469   client_->OnCanDrawStateChanged(CanDraw());
1470 }
1471
1472 CompositorFrameMetadata LayerTreeHostImpl::MakeCompositorFrameMetadata() const {
1473   CompositorFrameMetadata metadata;
1474   metadata.device_scale_factor = device_scale_factor_;
1475   metadata.page_scale_factor = active_tree_->total_page_scale_factor();
1476   metadata.scrollable_viewport_size = active_tree_->ScrollableViewportSize();
1477   metadata.root_layer_size = active_tree_->ScrollableSize();
1478   metadata.min_page_scale_factor = active_tree_->min_page_scale_factor();
1479   metadata.max_page_scale_factor = active_tree_->max_page_scale_factor();
1480   if (top_controls_manager_) {
1481     metadata.location_bar_offset =
1482         gfx::Vector2dF(0.f, top_controls_manager_->ControlsTopOffset());
1483     metadata.location_bar_content_translation =
1484         gfx::Vector2dF(0.f, top_controls_manager_->ContentTopOffset());
1485   }
1486
1487   active_tree_->GetViewportSelection(&metadata.selection_start,
1488                                      &metadata.selection_end);
1489
1490   if (!InnerViewportScrollLayer())
1491     return metadata;
1492
1493   // TODO(miletus) : Change the metadata to hold ScrollOffset.
1494   metadata.root_scroll_offset = gfx::ScrollOffsetToVector2dF(
1495       active_tree_->TotalScrollOffset());
1496
1497   return metadata;
1498 }
1499
1500 static void LayerTreeHostImplDidBeginTracingCallback(LayerImpl* layer) {
1501   layer->DidBeginTracing();
1502 }
1503
1504 void LayerTreeHostImpl::DrawLayers(FrameData* frame,
1505                                    base::TimeTicks frame_begin_time) {
1506   TRACE_EVENT0("cc", "LayerTreeHostImpl::DrawLayers");
1507   DCHECK(CanDraw());
1508
1509   if (frame->has_no_damage) {
1510     TRACE_EVENT_INSTANT0("cc", "EarlyOut_NoDamage", TRACE_EVENT_SCOPE_THREAD);
1511     DCHECK(!output_surface_->capabilities()
1512                .draw_and_swap_full_viewport_every_frame);
1513     return;
1514   }
1515
1516   DCHECK(!frame->render_passes.empty());
1517
1518   fps_counter_->SaveTimeStamp(frame_begin_time,
1519                               !output_surface_->context_provider());
1520   rendering_stats_instrumentation_->IncrementFrameCount(1);
1521
1522   if (tile_manager_) {
1523     memory_history_->SaveEntry(
1524         tile_manager_->memory_stats_from_last_assign());
1525   }
1526
1527   if (debug_state_.ShowHudRects()) {
1528     debug_rect_history_->SaveDebugRectsForCurrentFrame(
1529         active_tree_->root_layer(),
1530         active_tree_->hud_layer(),
1531         *frame->render_surface_layer_list,
1532         frame->occluding_screen_space_rects,
1533         frame->non_occluding_screen_space_rects,
1534         debug_state_);
1535   }
1536
1537   if (!settings_.impl_side_painting && debug_state_.continuous_painting) {
1538     const RenderingStats& stats =
1539         rendering_stats_instrumentation_->GetRenderingStats();
1540     paint_time_counter_->SavePaintTime(stats.main_stats.paint_time);
1541   }
1542
1543   bool is_new_trace;
1544   TRACE_EVENT_IS_NEW_TRACE(&is_new_trace);
1545   if (is_new_trace) {
1546     if (pending_tree_) {
1547       LayerTreeHostCommon::CallFunctionForSubtree(
1548           pending_tree_->root_layer(),
1549           base::Bind(&LayerTreeHostImplDidBeginTracingCallback));
1550     }
1551     LayerTreeHostCommon::CallFunctionForSubtree(
1552         active_tree_->root_layer(),
1553         base::Bind(&LayerTreeHostImplDidBeginTracingCallback));
1554   }
1555
1556   {
1557     TRACE_EVENT0("cc", "DrawLayers.FrameViewerTracing");
1558     TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(
1559        TRACE_DISABLED_BY_DEFAULT("cc.debug") ","
1560        TRACE_DISABLED_BY_DEFAULT("cc.debug.quads") ","
1561        TRACE_DISABLED_BY_DEFAULT("devtools.timeline.layers"),
1562        "cc::LayerTreeHostImpl",
1563        id_,
1564        AsValueWithFrame(frame));
1565   }
1566
1567   const DrawMode draw_mode = GetDrawMode();
1568
1569   // Because the contents of the HUD depend on everything else in the frame, the
1570   // contents of its texture are updated as the last thing before the frame is
1571   // drawn.
1572   if (active_tree_->hud_layer()) {
1573     TRACE_EVENT0("cc", "DrawLayers.UpdateHudTexture");
1574     active_tree_->hud_layer()->UpdateHudTexture(draw_mode,
1575                                                 resource_provider_.get());
1576   }
1577
1578   if (draw_mode == DRAW_MODE_RESOURCELESS_SOFTWARE) {
1579     bool disable_picture_quad_image_filtering =
1580         IsActivelyScrolling() || needs_animate_layers();
1581
1582     scoped_ptr<SoftwareRenderer> temp_software_renderer =
1583         SoftwareRenderer::Create(this, &settings_, output_surface_.get(), NULL);
1584     temp_software_renderer->DrawFrame(&frame->render_passes,
1585                                       device_scale_factor_,
1586                                       DeviceViewport(),
1587                                       DeviceClip(),
1588                                       disable_picture_quad_image_filtering);
1589   } else {
1590     renderer_->DrawFrame(&frame->render_passes,
1591                          device_scale_factor_,
1592                          DeviceViewport(),
1593                          DeviceClip(),
1594                          false);
1595   }
1596   // The render passes should be consumed by the renderer.
1597   DCHECK(frame->render_passes.empty());
1598   frame->render_passes_by_id.clear();
1599
1600   // The next frame should start by assuming nothing has changed, and changes
1601   // are noted as they occur.
1602   // TODO(boliu): If we did a temporary software renderer frame, propogate the
1603   // damage forward to the next frame.
1604   for (size_t i = 0; i < frame->render_surface_layer_list->size(); i++) {
1605     (*frame->render_surface_layer_list)[i]->render_surface()->damage_tracker()->
1606         DidDrawDamagedArea();
1607   }
1608   active_tree_->root_layer()->ResetAllChangeTrackingForSubtree();
1609
1610   active_tree_->set_has_ever_been_drawn(true);
1611   devtools_instrumentation::DidDrawFrame(id_);
1612   benchmark_instrumentation::IssueImplThreadRenderingStatsEvent(
1613       rendering_stats_instrumentation_->impl_thread_rendering_stats());
1614   rendering_stats_instrumentation_->AccumulateAndClearImplThreadStats();
1615 }
1616
1617 void LayerTreeHostImpl::DidDrawAllLayers(const FrameData& frame) {
1618   for (size_t i = 0; i < frame.will_draw_layers.size(); ++i)
1619     frame.will_draw_layers[i]->DidDraw(resource_provider_.get());
1620
1621   // Once all layers have been drawn, pending texture uploads should no
1622   // longer block future uploads.
1623   resource_provider_->MarkPendingUploadsAsNonBlocking();
1624 }
1625
1626 void LayerTreeHostImpl::FinishAllRendering() {
1627   if (renderer_)
1628     renderer_->Finish();
1629 }
1630
1631 void LayerTreeHostImpl::SetUseGpuRasterization(bool use_gpu) {
1632   if (use_gpu == use_gpu_rasterization_)
1633     return;
1634
1635   use_gpu_rasterization_ = use_gpu;
1636   ReleaseTreeResources();
1637
1638   // Replace existing tile manager with another one that uses appropriate
1639   // rasterizer.
1640   if (tile_manager_) {
1641     DestroyTileManager();
1642     CreateAndSetTileManager();
1643   }
1644
1645   // We have released tilings for both active and pending tree.
1646   // We would not have any content to draw until the pending tree is activated.
1647   // Prevent the active tree from drawing until activation.
1648   SetRequiresHighResToDraw();
1649 }
1650
1651 const RendererCapabilitiesImpl&
1652 LayerTreeHostImpl::GetRendererCapabilities() const {
1653   return renderer_->Capabilities();
1654 }
1655
1656 bool LayerTreeHostImpl::SwapBuffers(const LayerTreeHostImpl::FrameData& frame) {
1657   ResetRequiresHighResToDraw();
1658   if (frame.has_no_damage) {
1659     active_tree()->BreakSwapPromises(SwapPromise::SWAP_FAILS);
1660     return false;
1661   }
1662   CompositorFrameMetadata metadata = MakeCompositorFrameMetadata();
1663   active_tree()->FinishSwapPromises(&metadata);
1664   for (size_t i = 0; i < metadata.latency_info.size(); i++) {
1665     TRACE_EVENT_FLOW_STEP0(
1666         "input",
1667         "LatencyInfo.Flow",
1668         TRACE_ID_DONT_MANGLE(metadata.latency_info[i].trace_id),
1669         "SwapBuffers");
1670   }
1671   renderer_->SwapBuffers(metadata);
1672   return true;
1673 }
1674
1675 void LayerTreeHostImpl::OnNeedsBeginFramesChange(bool enable) {
1676   if (output_surface_)
1677     output_surface_->SetNeedsBeginFrame(enable);
1678   else
1679     DCHECK(!enable);
1680 }
1681
1682 void LayerTreeHostImpl::WillBeginImplFrame(const BeginFrameArgs& args) {
1683   // Sample the frame time now. This time will be used for updating animations
1684   // when we draw.
1685   UpdateCurrentBeginFrameArgs(args);
1686   // Cache the begin impl frame interval
1687   begin_impl_frame_interval_ = args.interval;
1688 }
1689
1690 void LayerTreeHostImpl::UpdateViewportContainerSizes() {
1691   LayerImpl* inner_container = active_tree_->InnerViewportContainerLayer();
1692   LayerImpl* outer_container = active_tree_->OuterViewportContainerLayer();
1693
1694   if (!inner_container || !top_controls_manager_)
1695     return;
1696
1697   ViewportAnchor anchor(InnerViewportScrollLayer(),
1698                         OuterViewportScrollLayer());
1699
1700   // Adjust the inner viewport by shrinking/expanding the container to account
1701   // for the change in top controls height since the last Resize from Blink.
1702   inner_container->SetBoundsDelta(
1703       gfx::Vector2dF(0, active_tree_->top_controls_layout_height() -
1704           active_tree_->total_top_controls_content_offset()));
1705
1706   if (!outer_container || outer_container->BoundsForScrolling().IsEmpty())
1707     return;
1708
1709   // Adjust the outer viewport container as well, since adjusting only the
1710   // inner may cause its bounds to exceed those of the outer, causing scroll
1711   // clamping. We adjust it so it maintains the same aspect ratio as the
1712   // inner viewport.
1713   float aspect_ratio = inner_container->BoundsForScrolling().width() /
1714       inner_container->BoundsForScrolling().height();
1715   float target_height = outer_container->BoundsForScrolling().width() /
1716       aspect_ratio;
1717   float current_outer_height = outer_container->BoundsForScrolling().height() -
1718       outer_container->bounds_delta().y();
1719   gfx::Vector2dF delta(0, target_height - current_outer_height);
1720
1721   outer_container->SetBoundsDelta(delta);
1722   active_tree_->InnerViewportScrollLayer()->SetBoundsDelta(delta);
1723
1724   anchor.ResetViewportToAnchoredPosition();
1725 }
1726
1727 void LayerTreeHostImpl::SetTopControlsLayoutHeight(float height) {
1728   if (active_tree_->top_controls_layout_height() == height)
1729     return;
1730
1731   active_tree_->set_top_controls_layout_height(height);
1732   UpdateViewportContainerSizes();
1733   SetFullRootLayerDamage();
1734 }
1735
1736 void LayerTreeHostImpl::SynchronouslyInitializeAllTiles() {
1737   // Only valid for the single-threaded non-scheduled/synchronous case
1738   // using the zero copy raster worker pool.
1739   single_thread_synchronous_task_graph_runner_->RunUntilIdle();
1740 }
1741
1742 void LayerTreeHostImpl::DidLoseOutputSurface() {
1743   if (resource_provider_)
1744     resource_provider_->DidLoseOutputSurface();
1745   client_->DidLoseOutputSurfaceOnImplThread();
1746 }
1747
1748 bool LayerTreeHostImpl::HaveRootScrollLayer() const {
1749   return !!InnerViewportScrollLayer();
1750 }
1751
1752 LayerImpl* LayerTreeHostImpl::RootLayer() const {
1753   return active_tree_->root_layer();
1754 }
1755
1756 LayerImpl* LayerTreeHostImpl::InnerViewportScrollLayer() const {
1757   return active_tree_->InnerViewportScrollLayer();
1758 }
1759
1760 LayerImpl* LayerTreeHostImpl::OuterViewportScrollLayer() const {
1761   return active_tree_->OuterViewportScrollLayer();
1762 }
1763
1764 LayerImpl* LayerTreeHostImpl::CurrentlyScrollingLayer() const {
1765   return active_tree_->CurrentlyScrollingLayer();
1766 }
1767
1768 bool LayerTreeHostImpl::IsActivelyScrolling() const {
1769   return (did_lock_scrolling_layer_ && CurrentlyScrollingLayer()) ||
1770          (InnerViewportScrollLayer() &&
1771           InnerViewportScrollLayer()->IsExternalFlingActive()) ||
1772          (OuterViewportScrollLayer() &&
1773           OuterViewportScrollLayer()->IsExternalFlingActive());
1774 }
1775
1776 // Content layers can be either directly scrollable or contained in an outer
1777 // scrolling layer which applies the scroll transform. Given a content layer,
1778 // this function returns the associated scroll layer if any.
1779 static LayerImpl* FindScrollLayerForContentLayer(LayerImpl* layer_impl) {
1780   if (!layer_impl)
1781     return NULL;
1782
1783   if (layer_impl->scrollable())
1784     return layer_impl;
1785
1786   if (layer_impl->DrawsContent() &&
1787       layer_impl->parent() &&
1788       layer_impl->parent()->scrollable())
1789     return layer_impl->parent();
1790
1791   return NULL;
1792 }
1793
1794 void LayerTreeHostImpl::CreatePendingTree() {
1795   CHECK(!pending_tree_);
1796   if (recycle_tree_)
1797     recycle_tree_.swap(pending_tree_);
1798   else
1799     pending_tree_ = LayerTreeImpl::create(this);
1800
1801   // Update the delta from the active tree, which may have
1802   // adjusted its delta prior to the pending tree being created.
1803   DCHECK_EQ(1.f, pending_tree_->sent_page_scale_delta());
1804   DCHECK_EQ(0.f, pending_tree_->sent_top_controls_delta());
1805   pending_tree_->SetPageScaleDelta(active_tree_->page_scale_delta() /
1806                                    active_tree_->sent_page_scale_delta());
1807   pending_tree_->set_top_controls_delta(
1808       active_tree_->top_controls_delta() -
1809       active_tree_->sent_top_controls_delta());
1810
1811   client_->OnCanDrawStateChanged(CanDraw());
1812   TRACE_EVENT_ASYNC_BEGIN0("cc", "PendingTree:waiting", pending_tree_.get());
1813 }
1814
1815 void LayerTreeHostImpl::UpdateVisibleTiles() {
1816   if (tile_manager_ && tile_manager_->UpdateVisibleTiles())
1817     DidInitializeVisibleTile();
1818   need_to_update_visible_tiles_before_draw_ = false;
1819 }
1820
1821 void LayerTreeHostImpl::ActivateSyncTree() {
1822   need_to_update_visible_tiles_before_draw_ = true;
1823
1824   if (pending_tree_) {
1825     TRACE_EVENT_ASYNC_END0("cc", "PendingTree:waiting", pending_tree_.get());
1826
1827     active_tree_->SetRootLayerScrollOffsetDelegate(NULL);
1828     active_tree_->PushPersistedState(pending_tree_.get());
1829     // Process any requests in the UI resource queue.  The request queue is
1830     // given in LayerTreeHost::FinishCommitOnImplThread.  This must take place
1831     // before the swap.
1832     pending_tree_->ProcessUIResourceRequestQueue();
1833
1834     if (pending_tree_->needs_full_tree_sync()) {
1835       active_tree_->SetRootLayer(
1836           TreeSynchronizer::SynchronizeTrees(pending_tree_->root_layer(),
1837                                              active_tree_->DetachLayerTree(),
1838                                              active_tree_.get()));
1839     }
1840     TreeSynchronizer::PushProperties(pending_tree_->root_layer(),
1841                                      active_tree_->root_layer());
1842     pending_tree_->PushPropertiesTo(active_tree_.get());
1843
1844     // Now that we've synced everything from the pending tree to the active
1845     // tree, rename the pending tree the recycle tree so we can reuse it on the
1846     // next sync.
1847     DCHECK(!recycle_tree_);
1848     pending_tree_.swap(recycle_tree_);
1849
1850     active_tree_->SetRootLayerScrollOffsetDelegate(
1851         root_layer_scroll_offset_delegate_);
1852
1853     if (top_controls_manager_) {
1854       top_controls_manager_->SetControlsTopOffset(
1855           active_tree_->total_top_controls_content_offset() -
1856           top_controls_manager_->top_controls_height());
1857     }
1858
1859     UpdateViewportContainerSizes();
1860   } else {
1861     active_tree_->ProcessUIResourceRequestQueue();
1862   }
1863
1864   active_tree_->DidBecomeActive();
1865   ActivateAnimations();
1866   if (settings_.impl_side_painting)
1867     client_->RenewTreePriority();
1868
1869   client_->OnCanDrawStateChanged(CanDraw());
1870   client_->DidActivateSyncTree();
1871   if (!tree_activation_callback_.is_null())
1872     tree_activation_callback_.Run();
1873
1874   if (debug_state_.continuous_painting) {
1875     const RenderingStats& stats =
1876         rendering_stats_instrumentation_->GetRenderingStats();
1877     paint_time_counter_->SavePaintTime(stats.main_stats.paint_time +
1878                                        stats.main_stats.record_time +
1879                                        stats.impl_stats.rasterize_time);
1880   }
1881
1882   if (time_source_client_adapter_ && time_source_client_adapter_->Active())
1883     DCHECK(active_tree_->root_layer());
1884
1885   scoped_ptr<PageScaleAnimation> page_scale_animation =
1886       active_tree_->TakePageScaleAnimation();
1887   if (page_scale_animation) {
1888     page_scale_animation_ = page_scale_animation.Pass();
1889     SetNeedsAnimate();
1890     client_->SetNeedsCommitOnImplThread();
1891     client_->RenewTreePriority();
1892   }
1893 }
1894
1895 void LayerTreeHostImpl::SetVisible(bool visible) {
1896   DCHECK(proxy_->IsImplThread());
1897
1898   if (visible_ == visible)
1899     return;
1900   visible_ = visible;
1901   DidVisibilityChange(this, visible_);
1902   EnforceManagedMemoryPolicy(ActualManagedMemoryPolicy());
1903
1904   // If we just became visible, we have to ensure that we draw high res tiles,
1905   // to prevent checkerboard/low res flashes.
1906   if (visible_)
1907     SetRequiresHighResToDraw();
1908   else
1909     EvictAllUIResources();
1910
1911   // Evict tiles immediately if invisible since this tab may never get another
1912   // draw or timer tick.
1913   if (!visible_)
1914     ManageTiles();
1915
1916   if (!renderer_)
1917     return;
1918
1919   renderer_->SetVisible(visible);
1920 }
1921
1922 void LayerTreeHostImpl::SetNeedsAnimate() {
1923   NotifySwapPromiseMonitorsOfSetNeedsRedraw();
1924   client_->SetNeedsAnimateOnImplThread();
1925 }
1926
1927 void LayerTreeHostImpl::SetNeedsRedraw() {
1928   NotifySwapPromiseMonitorsOfSetNeedsRedraw();
1929   client_->SetNeedsRedrawOnImplThread();
1930 }
1931
1932 ManagedMemoryPolicy LayerTreeHostImpl::ActualManagedMemoryPolicy() const {
1933   ManagedMemoryPolicy actual = cached_managed_memory_policy_;
1934   if (debug_state_.rasterize_only_visible_content) {
1935     actual.priority_cutoff_when_visible =
1936         gpu::MemoryAllocation::CUTOFF_ALLOW_REQUIRED_ONLY;
1937   } else if (use_gpu_rasterization()) {
1938     actual.priority_cutoff_when_visible =
1939         gpu::MemoryAllocation::CUTOFF_ALLOW_NICE_TO_HAVE;
1940   }
1941
1942   if (zero_budget_) {
1943     actual.bytes_limit_when_visible = 0;
1944   }
1945
1946   return actual;
1947 }
1948
1949 size_t LayerTreeHostImpl::memory_allocation_limit_bytes() const {
1950   return ActualManagedMemoryPolicy().bytes_limit_when_visible;
1951 }
1952
1953 int LayerTreeHostImpl::memory_allocation_priority_cutoff() const {
1954   return ManagedMemoryPolicy::PriorityCutoffToValue(
1955       ActualManagedMemoryPolicy().priority_cutoff_when_visible);
1956 }
1957
1958 void LayerTreeHostImpl::ReleaseTreeResources() {
1959   active_tree_->ReleaseResources();
1960   if (pending_tree_)
1961     pending_tree_->ReleaseResources();
1962   if (recycle_tree_)
1963     recycle_tree_->ReleaseResources();
1964
1965   EvictAllUIResources();
1966 }
1967
1968 void LayerTreeHostImpl::CreateAndSetRenderer() {
1969   DCHECK(!renderer_);
1970   DCHECK(output_surface_);
1971   DCHECK(resource_provider_);
1972
1973   if (output_surface_->capabilities().delegated_rendering) {
1974     renderer_ = DelegatingRenderer::Create(
1975         this, &settings_, output_surface_.get(), resource_provider_.get());
1976   } else if (output_surface_->context_provider()) {
1977     renderer_ = GLRenderer::Create(this,
1978                                    &settings_,
1979                                    output_surface_.get(),
1980                                    resource_provider_.get(),
1981                                    texture_mailbox_deleter_.get(),
1982                                    settings_.highp_threshold_min);
1983   } else if (output_surface_->software_device()) {
1984     renderer_ = SoftwareRenderer::Create(
1985         this, &settings_, output_surface_.get(), resource_provider_.get());
1986   }
1987   DCHECK(renderer_);
1988
1989   renderer_->SetVisible(visible_);
1990   SetFullRootLayerDamage();
1991
1992   // See note in LayerTreeImpl::UpdateDrawProperties.  Renderer needs to be
1993   // initialized to get max texture size.  Also, after releasing resources,
1994   // trees need another update to generate new ones.
1995   active_tree_->set_needs_update_draw_properties();
1996   if (pending_tree_)
1997     pending_tree_->set_needs_update_draw_properties();
1998   client_->UpdateRendererCapabilitiesOnImplThread();
1999 }
2000
2001 void LayerTreeHostImpl::CreateAndSetTileManager() {
2002   DCHECK(!tile_manager_);
2003   DCHECK(settings_.impl_side_painting);
2004   DCHECK(output_surface_);
2005   DCHECK(resource_provider_);
2006
2007   CreateResourceAndRasterWorkerPool(
2008       &raster_worker_pool_, &resource_pool_, &staging_resource_pool_);
2009   DCHECK(raster_worker_pool_);
2010   DCHECK(resource_pool_);
2011
2012   base::SingleThreadTaskRunner* task_runner =
2013       proxy_->HasImplThread() ? proxy_->ImplThreadTaskRunner()
2014                               : proxy_->MainThreadTaskRunner();
2015   DCHECK(task_runner);
2016   size_t scheduled_raster_task_limit =
2017       IsSynchronousSingleThreaded() ? std::numeric_limits<size_t>::max()
2018                                     : settings_.scheduled_raster_task_limit;
2019   tile_manager_ = TileManager::Create(this,
2020                                       task_runner,
2021                                       resource_pool_.get(),
2022                                       raster_worker_pool_->AsRasterizer(),
2023                                       rendering_stats_instrumentation_,
2024                                       scheduled_raster_task_limit);
2025
2026   UpdateTileManagerMemoryPolicy(ActualManagedMemoryPolicy());
2027   need_to_update_visible_tiles_before_draw_ = false;
2028 }
2029
2030 void LayerTreeHostImpl::CreateResourceAndRasterWorkerPool(
2031     scoped_ptr<RasterWorkerPool>* raster_worker_pool,
2032     scoped_ptr<ResourcePool>* resource_pool,
2033     scoped_ptr<ResourcePool>* staging_resource_pool) {
2034   base::SingleThreadTaskRunner* task_runner =
2035       proxy_->HasImplThread() ? proxy_->ImplThreadTaskRunner()
2036                               : proxy_->MainThreadTaskRunner();
2037   DCHECK(task_runner);
2038
2039   ContextProvider* context_provider = output_surface_->context_provider();
2040   bool should_use_zero_copy_rasterizer =
2041       settings_.use_zero_copy || IsSynchronousSingleThreaded();
2042
2043   if (!context_provider) {
2044     *resource_pool =
2045         ResourcePool::Create(resource_provider_.get(),
2046                              GL_TEXTURE_2D,
2047                              resource_provider_->best_texture_format());
2048
2049     *raster_worker_pool =
2050         BitmapRasterWorkerPool::Create(task_runner,
2051                                        RasterWorkerPool::GetTaskGraphRunner(),
2052                                        resource_provider_.get());
2053   } else if (use_gpu_rasterization_) {
2054     *resource_pool =
2055         ResourcePool::Create(resource_provider_.get(),
2056                              GL_TEXTURE_2D,
2057                              resource_provider_->best_texture_format());
2058
2059     *raster_worker_pool =
2060         GpuRasterWorkerPool::Create(task_runner,
2061                                     context_provider,
2062                                     resource_provider_.get(),
2063                                     settings_.use_distance_field_text);
2064   } else if (should_use_zero_copy_rasterizer && CanUseZeroCopyRasterizer()) {
2065     *resource_pool = ResourcePool::Create(
2066         resource_provider_.get(),
2067         GetMapImageTextureTarget(context_provider->ContextCapabilities()),
2068         resource_provider_->best_texture_format());
2069
2070     TaskGraphRunner* task_graph_runner;
2071     if (IsSynchronousSingleThreaded()) {
2072       DCHECK(!single_thread_synchronous_task_graph_runner_);
2073       single_thread_synchronous_task_graph_runner_.reset(new TaskGraphRunner);
2074       task_graph_runner = single_thread_synchronous_task_graph_runner_.get();
2075     } else {
2076       task_graph_runner = RasterWorkerPool::GetTaskGraphRunner();
2077     }
2078
2079     *raster_worker_pool = ZeroCopyRasterWorkerPool::Create(
2080         task_runner, task_graph_runner, resource_provider_.get());
2081   } else if (settings_.use_one_copy && CanUseOneCopyRasterizer()) {
2082     // We need to create a staging resource pool when using copy rasterizer.
2083     *staging_resource_pool = ResourcePool::Create(
2084         resource_provider_.get(),
2085         GetMapImageTextureTarget(context_provider->ContextCapabilities()),
2086         resource_provider_->best_texture_format());
2087     *resource_pool =
2088         ResourcePool::Create(resource_provider_.get(),
2089                              GL_TEXTURE_2D,
2090                              resource_provider_->best_texture_format());
2091
2092     *raster_worker_pool =
2093         OneCopyRasterWorkerPool::Create(task_runner,
2094                                         RasterWorkerPool::GetTaskGraphRunner(),
2095                                         context_provider,
2096                                         resource_provider_.get(),
2097                                         staging_resource_pool_.get());
2098   } else {
2099     *resource_pool = ResourcePool::Create(
2100         resource_provider_.get(),
2101         GL_TEXTURE_2D,
2102         resource_provider_->memory_efficient_texture_format());
2103
2104     *raster_worker_pool = PixelBufferRasterWorkerPool::Create(
2105         task_runner,
2106         RasterWorkerPool::GetTaskGraphRunner(),
2107         context_provider,
2108         resource_provider_.get(),
2109         GetMaxTransferBufferUsageBytes(context_provider->ContextCapabilities(),
2110                                        settings_.refresh_rate));
2111   }
2112 }
2113
2114 void LayerTreeHostImpl::DestroyTileManager() {
2115   tile_manager_ = nullptr;
2116   resource_pool_ = nullptr;
2117   staging_resource_pool_ = nullptr;
2118   raster_worker_pool_ = nullptr;
2119   single_thread_synchronous_task_graph_runner_ = nullptr;
2120 }
2121
2122 bool LayerTreeHostImpl::UsePendingTreeForSync() const {
2123   // In impl-side painting, synchronize to the pending tree so that it has
2124   // time to raster before being displayed.
2125   return settings_.impl_side_painting;
2126 }
2127
2128 bool LayerTreeHostImpl::IsSynchronousSingleThreaded() const {
2129   return !proxy_->HasImplThread() && !settings_.single_thread_proxy_scheduler;
2130 }
2131
2132 bool LayerTreeHostImpl::CanUseZeroCopyRasterizer() const {
2133   return GetRendererCapabilities().using_image;
2134 }
2135
2136 bool LayerTreeHostImpl::CanUseOneCopyRasterizer() const {
2137   // Sync query support is required by one-copy rasterizer.
2138   return GetRendererCapabilities().using_image &&
2139          resource_provider_->use_sync_query();
2140 }
2141
2142 void LayerTreeHostImpl::EnforceZeroBudget(bool zero_budget) {
2143   SetManagedMemoryPolicy(cached_managed_memory_policy_, zero_budget);
2144 }
2145
2146 bool LayerTreeHostImpl::InitializeRenderer(
2147     scoped_ptr<OutputSurface> output_surface) {
2148   TRACE_EVENT0("cc", "LayerTreeHostImpl::InitializeRenderer");
2149
2150   // Since we will create a new resource provider, we cannot continue to use
2151   // the old resources (i.e. render_surfaces and texture IDs). Clear them
2152   // before we destroy the old resource provider.
2153   ReleaseTreeResources();
2154
2155   // Note: order is important here.
2156   renderer_ = nullptr;
2157   DestroyTileManager();
2158   resource_provider_ = nullptr;
2159   output_surface_ = nullptr;
2160
2161   if (!output_surface->BindToClient(this))
2162     return false;
2163
2164   output_surface_ = output_surface.Pass();
2165   resource_provider_ =
2166       ResourceProvider::Create(output_surface_.get(),
2167                                shared_bitmap_manager_,
2168                                gpu_memory_buffer_manager_,
2169                                proxy_->blocking_main_thread_task_runner(),
2170                                settings_.highp_threshold_min,
2171                                settings_.use_rgba_4444_textures,
2172                                settings_.texture_id_allocation_chunk_size);
2173
2174   if (output_surface_->capabilities().deferred_gl_initialization)
2175     EnforceZeroBudget(true);
2176
2177   CreateAndSetRenderer();
2178
2179   if (settings_.impl_side_painting)
2180     CreateAndSetTileManager();
2181
2182   // Initialize vsync parameters to sane values.
2183   const base::TimeDelta display_refresh_interval =
2184       base::TimeDelta::FromMicroseconds(base::Time::kMicrosecondsPerSecond /
2185                                         settings_.refresh_rate);
2186   CommitVSyncParameters(base::TimeTicks(), display_refresh_interval);
2187
2188   // TODO(brianderson): Don't use a hard-coded parent draw time.
2189   base::TimeDelta parent_draw_time =
2190       (!settings_.begin_frame_scheduling_enabled &&
2191        output_surface_->capabilities().adjust_deadline_for_parent)
2192           ? BeginFrameArgs::DefaultEstimatedParentDrawTime()
2193           : base::TimeDelta();
2194   client_->SetEstimatedParentDrawTime(parent_draw_time);
2195
2196   int max_frames_pending = output_surface_->capabilities().max_frames_pending;
2197   if (max_frames_pending <= 0)
2198     max_frames_pending = OutputSurface::DEFAULT_MAX_FRAMES_PENDING;
2199   client_->SetMaxSwapsPendingOnImplThread(max_frames_pending);
2200   client_->OnCanDrawStateChanged(CanDraw());
2201
2202   // There will not be anything to draw here, so set high res
2203   // to avoid checkerboards, typically when we are recovering
2204   // from lost context.
2205   SetRequiresHighResToDraw();
2206
2207   return true;
2208 }
2209
2210 void LayerTreeHostImpl::CommitVSyncParameters(base::TimeTicks timebase,
2211                                               base::TimeDelta interval) {
2212   client_->CommitVSyncParameters(timebase, interval);
2213 }
2214
2215 void LayerTreeHostImpl::DeferredInitialize() {
2216   DCHECK(output_surface_->capabilities().deferred_gl_initialization);
2217   DCHECK(settings_.impl_side_painting);
2218   DCHECK(output_surface_->context_provider());
2219
2220   ReleaseTreeResources();
2221   renderer_ = nullptr;
2222   DestroyTileManager();
2223
2224   resource_provider_->InitializeGL();
2225
2226   CreateAndSetRenderer();
2227   EnforceZeroBudget(false);
2228   CreateAndSetTileManager();
2229
2230   client_->SetNeedsCommitOnImplThread();
2231 }
2232
2233 void LayerTreeHostImpl::ReleaseGL() {
2234   DCHECK(output_surface_->capabilities().deferred_gl_initialization);
2235   DCHECK(settings_.impl_side_painting);
2236   DCHECK(output_surface_->context_provider());
2237
2238   ReleaseTreeResources();
2239   renderer_ = nullptr;
2240   DestroyTileManager();
2241
2242   resource_provider_->InitializeSoftware();
2243   output_surface_->ReleaseContextProvider();
2244
2245   CreateAndSetRenderer();
2246   EnforceZeroBudget(true);
2247   CreateAndSetTileManager();
2248
2249   client_->SetNeedsCommitOnImplThread();
2250 }
2251
2252 void LayerTreeHostImpl::SetViewportSize(const gfx::Size& device_viewport_size) {
2253   if (device_viewport_size == device_viewport_size_)
2254     return;
2255
2256   if (pending_tree_)
2257     active_tree_->SetViewportSizeInvalid();
2258
2259   device_viewport_size_ = device_viewport_size;
2260
2261   UpdateViewportContainerSizes();
2262   client_->OnCanDrawStateChanged(CanDraw());
2263   SetFullRootLayerDamage();
2264   active_tree_->set_needs_update_draw_properties();
2265 }
2266
2267 void LayerTreeHostImpl::SetOverhangUIResource(
2268     UIResourceId overhang_ui_resource_id,
2269     const gfx::Size& overhang_ui_resource_size) {
2270   overhang_ui_resource_id_ = overhang_ui_resource_id;
2271   overhang_ui_resource_size_ = overhang_ui_resource_size;
2272 }
2273
2274 void LayerTreeHostImpl::SetDeviceScaleFactor(float device_scale_factor) {
2275   if (device_scale_factor == device_scale_factor_)
2276     return;
2277   device_scale_factor_ = device_scale_factor;
2278
2279   SetFullRootLayerDamage();
2280 }
2281
2282 const gfx::Rect LayerTreeHostImpl::ViewportRectForTilePriority() const {
2283   if (viewport_rect_for_tile_priority_.IsEmpty())
2284     return DeviceViewport();
2285
2286   return viewport_rect_for_tile_priority_;
2287 }
2288
2289 gfx::Size LayerTreeHostImpl::DrawViewportSize() const {
2290   return DeviceViewport().size();
2291 }
2292
2293 gfx::Rect LayerTreeHostImpl::DeviceViewport() const {
2294   if (external_viewport_.IsEmpty())
2295     return gfx::Rect(device_viewport_size_);
2296
2297   return external_viewport_;
2298 }
2299
2300 gfx::Rect LayerTreeHostImpl::DeviceClip() const {
2301   if (external_clip_.IsEmpty())
2302     return DeviceViewport();
2303
2304   return external_clip_;
2305 }
2306
2307 const gfx::Transform& LayerTreeHostImpl::DrawTransform() const {
2308   return external_transform_;
2309 }
2310
2311 void LayerTreeHostImpl::DidChangeTopControlsPosition() {
2312   UpdateViewportContainerSizes();
2313   SetNeedsRedraw();
2314   SetNeedsAnimate();
2315   active_tree_->set_needs_update_draw_properties();
2316   SetFullRootLayerDamage();
2317 }
2318
2319 void LayerTreeHostImpl::SetControlsTopOffset(float offset) {
2320   float current_top_offset = active_tree_->top_controls_content_offset() -
2321       top_controls_manager_->top_controls_height();
2322   active_tree_->set_top_controls_delta(offset - current_top_offset);
2323 }
2324
2325 float LayerTreeHostImpl::ControlsTopOffset() const {
2326   return active_tree_->total_top_controls_content_offset() -
2327       top_controls_manager_->top_controls_height();
2328 }
2329
2330 void LayerTreeHostImpl::BindToClient(InputHandlerClient* client) {
2331   DCHECK(input_handler_client_ == NULL);
2332   input_handler_client_ = client;
2333 }
2334
2335 static LayerImpl* NextScrollLayer(LayerImpl* layer) {
2336   if (LayerImpl* scroll_parent = layer->scroll_parent())
2337     return scroll_parent;
2338   return layer->parent();
2339 }
2340
2341 LayerImpl* LayerTreeHostImpl::FindScrollLayerForDeviceViewportPoint(
2342     const gfx::PointF& device_viewport_point,
2343     InputHandler::ScrollInputType type,
2344     LayerImpl* layer_impl,
2345     bool* scroll_on_main_thread,
2346     bool* optional_has_ancestor_scroll_handler) const {
2347   DCHECK(scroll_on_main_thread);
2348
2349   // Walk up the hierarchy and look for a scrollable layer.
2350   LayerImpl* potentially_scrolling_layer_impl = NULL;
2351   for (; layer_impl; layer_impl = NextScrollLayer(layer_impl)) {
2352     // The content layer can also block attempts to scroll outside the main
2353     // thread.
2354     ScrollStatus status = layer_impl->TryScroll(device_viewport_point, type);
2355     if (status == ScrollOnMainThread) {
2356       *scroll_on_main_thread = true;
2357       return NULL;
2358     }
2359
2360     LayerImpl* scroll_layer_impl = FindScrollLayerForContentLayer(layer_impl);
2361     if (!scroll_layer_impl)
2362       continue;
2363
2364     status = scroll_layer_impl->TryScroll(device_viewport_point, type);
2365     // If any layer wants to divert the scroll event to the main thread, abort.
2366     if (status == ScrollOnMainThread) {
2367       *scroll_on_main_thread = true;
2368       return NULL;
2369     }
2370
2371     if (optional_has_ancestor_scroll_handler &&
2372         scroll_layer_impl->have_scroll_event_handlers())
2373       *optional_has_ancestor_scroll_handler = true;
2374
2375     if (status == ScrollStarted && !potentially_scrolling_layer_impl)
2376       potentially_scrolling_layer_impl = scroll_layer_impl;
2377   }
2378
2379   // Falling back to the root scroll layer ensures generation of root overscroll
2380   // notifications while preventing scroll updates from being unintentionally
2381   // forwarded to the main thread.
2382   if (!potentially_scrolling_layer_impl)
2383     potentially_scrolling_layer_impl = OuterViewportScrollLayer()
2384                                            ? OuterViewportScrollLayer()
2385                                            : InnerViewportScrollLayer();
2386
2387   return potentially_scrolling_layer_impl;
2388 }
2389
2390 // Similar to LayerImpl::HasAncestor, but walks up the scroll parents.
2391 static bool HasScrollAncestor(LayerImpl* child, LayerImpl* scroll_ancestor) {
2392   DCHECK(scroll_ancestor);
2393   for (LayerImpl* ancestor = child; ancestor;
2394        ancestor = NextScrollLayer(ancestor)) {
2395     if (ancestor->scrollable())
2396       return ancestor == scroll_ancestor;
2397   }
2398   return false;
2399 }
2400
2401 InputHandler::ScrollStatus LayerTreeHostImpl::ScrollBegin(
2402     const gfx::Point& viewport_point,
2403     InputHandler::ScrollInputType type) {
2404   TRACE_EVENT0("cc", "LayerTreeHostImpl::ScrollBegin");
2405
2406   if (top_controls_manager_)
2407     top_controls_manager_->ScrollBegin();
2408
2409   DCHECK(!CurrentlyScrollingLayer());
2410   ClearCurrentlyScrollingLayer();
2411
2412   gfx::PointF device_viewport_point = gfx::ScalePoint(viewport_point,
2413                                                       device_scale_factor_);
2414   LayerImpl* layer_impl =
2415       active_tree_->FindLayerThatIsHitByPoint(device_viewport_point);
2416
2417   if (layer_impl) {
2418     LayerImpl* scroll_layer_impl =
2419         active_tree_->FindFirstScrollingLayerThatIsHitByPoint(
2420             device_viewport_point);
2421     if (scroll_layer_impl && !HasScrollAncestor(layer_impl, scroll_layer_impl))
2422       return ScrollUnknown;
2423   }
2424
2425   bool scroll_on_main_thread = false;
2426   LayerImpl* scrolling_layer_impl =
2427       FindScrollLayerForDeviceViewportPoint(device_viewport_point,
2428                                             type,
2429                                             layer_impl,
2430                                             &scroll_on_main_thread,
2431                                             &scroll_affects_scroll_handler_);
2432
2433   if (scroll_on_main_thread) {
2434     UMA_HISTOGRAM_BOOLEAN("TryScroll.SlowScroll", true);
2435     return ScrollOnMainThread;
2436   }
2437
2438   if (scrolling_layer_impl) {
2439     active_tree_->SetCurrentlyScrollingLayer(scrolling_layer_impl);
2440     should_bubble_scrolls_ = (type != NonBubblingGesture);
2441     wheel_scrolling_ = (type == Wheel);
2442     client_->RenewTreePriority();
2443     UMA_HISTOGRAM_BOOLEAN("TryScroll.SlowScroll", false);
2444     return ScrollStarted;
2445   }
2446   return ScrollIgnored;
2447 }
2448
2449 InputHandler::ScrollStatus LayerTreeHostImpl::ScrollAnimated(
2450     const gfx::Point& viewport_point,
2451     const gfx::Vector2dF& scroll_delta) {
2452   if (LayerImpl* layer_impl = CurrentlyScrollingLayer()) {
2453     Animation* animation =
2454         layer_impl->layer_animation_controller()->GetAnimation(
2455             Animation::ScrollOffset);
2456     if (!animation)
2457       return ScrollIgnored;
2458
2459     ScrollOffsetAnimationCurve* curve =
2460         animation->curve()->ToScrollOffsetAnimationCurve();
2461
2462     gfx::ScrollOffset new_target =
2463         gfx::ScrollOffsetWithDelta(curve->target_value(), scroll_delta);
2464     new_target.SetToMax(gfx::ScrollOffset());
2465     new_target.SetToMin(layer_impl->MaxScrollOffset());
2466
2467     curve->UpdateTarget(animation->TrimTimeToCurrentIteration(
2468                             CurrentBeginFrameArgs().frame_time),
2469                         new_target);
2470
2471     return ScrollStarted;
2472   }
2473   // ScrollAnimated is only used for wheel scrolls. We use the same bubbling
2474   // behavior as ScrollBy to determine which layer to animate, but we do not
2475   // do the Android-specific things in ScrollBy like showing top controls.
2476   InputHandler::ScrollStatus scroll_status = ScrollBegin(viewport_point, Wheel);
2477   if (scroll_status == ScrollStarted) {
2478     gfx::Vector2dF pending_delta = scroll_delta;
2479     for (LayerImpl* layer_impl = CurrentlyScrollingLayer(); layer_impl;
2480          layer_impl = layer_impl->parent()) {
2481       if (!layer_impl->scrollable())
2482         continue;
2483
2484       gfx::ScrollOffset current_offset = layer_impl->TotalScrollOffset();
2485       gfx::ScrollOffset target_offset =
2486           ScrollOffsetWithDelta(current_offset, pending_delta);
2487       target_offset.SetToMax(gfx::ScrollOffset());
2488       target_offset.SetToMin(layer_impl->MaxScrollOffset());
2489       gfx::Vector2dF actual_delta = target_offset.DeltaFrom(current_offset);
2490
2491       const float kEpsilon = 0.1f;
2492       bool can_layer_scroll = (std::abs(actual_delta.x()) > kEpsilon ||
2493                                std::abs(actual_delta.y()) > kEpsilon);
2494
2495       if (!can_layer_scroll) {
2496         layer_impl->ScrollBy(actual_delta);
2497         pending_delta -= actual_delta;
2498         continue;
2499       }
2500
2501       active_tree_->SetCurrentlyScrollingLayer(layer_impl);
2502
2503       scoped_ptr<ScrollOffsetAnimationCurve> curve =
2504           ScrollOffsetAnimationCurve::Create(target_offset,
2505                                              EaseInOutTimingFunction::Create());
2506       curve->SetInitialValue(current_offset);
2507
2508       scoped_ptr<Animation> animation =
2509           Animation::Create(curve.Pass(),
2510                             AnimationIdProvider::NextAnimationId(),
2511                             AnimationIdProvider::NextGroupId(),
2512                             Animation::ScrollOffset);
2513       animation->set_is_impl_only(true);
2514
2515       layer_impl->layer_animation_controller()->AddAnimation(animation.Pass());
2516
2517       SetNeedsAnimate();
2518       return ScrollStarted;
2519     }
2520   }
2521   ScrollEnd();
2522   return scroll_status;
2523 }
2524
2525 gfx::Vector2dF LayerTreeHostImpl::ScrollLayerWithViewportSpaceDelta(
2526     LayerImpl* layer_impl,
2527     float scale_from_viewport_to_screen_space,
2528     const gfx::PointF& viewport_point,
2529     const gfx::Vector2dF& viewport_delta) {
2530   // Layers with non-invertible screen space transforms should not have passed
2531   // the scroll hit test in the first place.
2532   DCHECK(layer_impl->screen_space_transform().IsInvertible());
2533   gfx::Transform inverse_screen_space_transform(
2534       gfx::Transform::kSkipInitialization);
2535   bool did_invert = layer_impl->screen_space_transform().GetInverse(
2536       &inverse_screen_space_transform);
2537   // TODO(shawnsingh): With the advent of impl-side crolling for non-root
2538   // layers, we may need to explicitly handle uninvertible transforms here.
2539   DCHECK(did_invert);
2540
2541   gfx::PointF screen_space_point =
2542       gfx::ScalePoint(viewport_point, scale_from_viewport_to_screen_space);
2543
2544   gfx::Vector2dF screen_space_delta = viewport_delta;
2545   screen_space_delta.Scale(scale_from_viewport_to_screen_space);
2546
2547   // First project the scroll start and end points to local layer space to find
2548   // the scroll delta in layer coordinates.
2549   bool start_clipped, end_clipped;
2550   gfx::PointF screen_space_end_point = screen_space_point + screen_space_delta;
2551   gfx::PointF local_start_point =
2552       MathUtil::ProjectPoint(inverse_screen_space_transform,
2553                              screen_space_point,
2554                              &start_clipped);
2555   gfx::PointF local_end_point =
2556       MathUtil::ProjectPoint(inverse_screen_space_transform,
2557                              screen_space_end_point,
2558                              &end_clipped);
2559
2560   // In general scroll point coordinates should not get clipped.
2561   DCHECK(!start_clipped);
2562   DCHECK(!end_clipped);
2563   if (start_clipped || end_clipped)
2564     return gfx::Vector2dF();
2565
2566   // local_start_point and local_end_point are in content space but we want to
2567   // move them to layer space for scrolling.
2568   float width_scale = 1.f / layer_impl->contents_scale_x();
2569   float height_scale = 1.f / layer_impl->contents_scale_y();
2570   local_start_point.Scale(width_scale, height_scale);
2571   local_end_point.Scale(width_scale, height_scale);
2572
2573   // Apply the scroll delta.
2574   gfx::Vector2dF previous_delta = layer_impl->ScrollDelta();
2575   layer_impl->ScrollBy(local_end_point - local_start_point);
2576
2577   // Get the end point in the layer's content space so we can apply its
2578   // ScreenSpaceTransform.
2579   gfx::PointF actual_local_end_point = local_start_point +
2580                                        layer_impl->ScrollDelta() -
2581                                        previous_delta;
2582   gfx::PointF actual_local_content_end_point =
2583       gfx::ScalePoint(actual_local_end_point,
2584                       1.f / width_scale,
2585                       1.f / height_scale);
2586
2587   // Calculate the applied scroll delta in viewport space coordinates.
2588   gfx::PointF actual_screen_space_end_point =
2589       MathUtil::MapPoint(layer_impl->screen_space_transform(),
2590                          actual_local_content_end_point,
2591                          &end_clipped);
2592   DCHECK(!end_clipped);
2593   if (end_clipped)
2594     return gfx::Vector2dF();
2595   gfx::PointF actual_viewport_end_point =
2596       gfx::ScalePoint(actual_screen_space_end_point,
2597                       1.f / scale_from_viewport_to_screen_space);
2598   return actual_viewport_end_point - viewport_point;
2599 }
2600
2601 static gfx::Vector2dF ScrollLayerWithLocalDelta(LayerImpl* layer_impl,
2602     const gfx::Vector2dF& local_delta) {
2603   gfx::Vector2dF previous_delta(layer_impl->ScrollDelta());
2604   layer_impl->ScrollBy(local_delta);
2605   return layer_impl->ScrollDelta() - previous_delta;
2606 }
2607
2608 bool LayerTreeHostImpl::ShouldTopControlsConsumeScroll(
2609     const gfx::Vector2dF& scroll_delta) const {
2610   DCHECK(CurrentlyScrollingLayer());
2611
2612   if (!top_controls_manager_)
2613     return false;
2614
2615   // Always consume if it's in the direction to show the top controls.
2616   if (scroll_delta.y() < 0)
2617     return true;
2618
2619   if (CurrentlyScrollingLayer() != InnerViewportScrollLayer() &&
2620       CurrentlyScrollingLayer() != OuterViewportScrollLayer())
2621     return false;
2622
2623   if (InnerViewportScrollLayer()->MaxScrollOffset().y() > 0)
2624     return true;
2625
2626   if (OuterViewportScrollLayer() &&
2627       OuterViewportScrollLayer()->MaxScrollOffset().y() > 0)
2628     return true;
2629
2630   return false;
2631 }
2632
2633 bool LayerTreeHostImpl::ScrollBy(const gfx::Point& viewport_point,
2634                                  const gfx::Vector2dF& scroll_delta) {
2635   TRACE_EVENT0("cc", "LayerTreeHostImpl::ScrollBy");
2636   if (!CurrentlyScrollingLayer())
2637     return false;
2638
2639   gfx::Vector2dF pending_delta = scroll_delta;
2640   gfx::Vector2dF unused_root_delta;
2641   bool did_scroll_x = false;
2642   bool did_scroll_y = false;
2643   bool did_scroll_top_controls = false;
2644
2645   bool consume_by_top_controls = ShouldTopControlsConsumeScroll(scroll_delta);
2646
2647   for (LayerImpl* layer_impl = CurrentlyScrollingLayer();
2648        layer_impl;
2649        layer_impl = layer_impl->parent()) {
2650     if (!layer_impl->scrollable())
2651       continue;
2652
2653     if (layer_impl == InnerViewportScrollLayer() ||
2654         layer_impl == OuterViewportScrollLayer()) {
2655       if (consume_by_top_controls) {
2656         gfx::Vector2dF excess_delta =
2657             top_controls_manager_->ScrollBy(pending_delta);
2658         gfx::Vector2dF applied_delta = pending_delta - excess_delta;
2659         pending_delta = excess_delta;
2660         // Force updating of vertical adjust values if needed.
2661         if (applied_delta.y() != 0)
2662           did_scroll_top_controls = true;
2663       }
2664       // Track root layer deltas for reporting overscroll.
2665       if (layer_impl == InnerViewportScrollLayer())
2666         unused_root_delta = pending_delta;
2667     }
2668
2669     gfx::Vector2dF applied_delta;
2670     // Gesture events need to be transformed from viewport coordinates to local
2671     // layer coordinates so that the scrolling contents exactly follow the
2672     // user's finger. In contrast, wheel events represent a fixed amount of
2673     // scrolling so we can just apply them directly.
2674     if (!wheel_scrolling_) {
2675       float scale_from_viewport_to_screen_space = device_scale_factor_;
2676       applied_delta =
2677           ScrollLayerWithViewportSpaceDelta(layer_impl,
2678                                             scale_from_viewport_to_screen_space,
2679                                             viewport_point, pending_delta);
2680     } else {
2681       applied_delta = ScrollLayerWithLocalDelta(layer_impl, pending_delta);
2682     }
2683
2684     const float kEpsilon = 0.1f;
2685     if (layer_impl == InnerViewportScrollLayer()) {
2686       unused_root_delta.Subtract(applied_delta);
2687       if (std::abs(unused_root_delta.x()) < kEpsilon)
2688         unused_root_delta.set_x(0.0f);
2689       if (std::abs(unused_root_delta.y()) < kEpsilon)
2690         unused_root_delta.set_y(0.0f);
2691       // Disable overscroll on axes which is impossible to scroll.
2692       if (settings_.report_overscroll_only_for_scrollable_axes) {
2693         if (std::abs(active_tree_->TotalMaxScrollOffset().x()) <= kEpsilon ||
2694             !layer_impl->user_scrollable_horizontal())
2695           unused_root_delta.set_x(0.0f);
2696         if (std::abs(active_tree_->TotalMaxScrollOffset().y()) <= kEpsilon ||
2697             !layer_impl->user_scrollable_vertical())
2698           unused_root_delta.set_y(0.0f);
2699       }
2700     }
2701
2702     // If the layer wasn't able to move, try the next one in the hierarchy.
2703     bool did_move_layer_x = std::abs(applied_delta.x()) > kEpsilon;
2704     bool did_move_layer_y = std::abs(applied_delta.y()) > kEpsilon;
2705     did_scroll_x |= did_move_layer_x;
2706     did_scroll_y |= did_move_layer_y;
2707     if (!did_move_layer_x && !did_move_layer_y) {
2708       // Scrolls should always bubble between the outer and inner viewports
2709       if (should_bubble_scrolls_ || !did_lock_scrolling_layer_ ||
2710           layer_impl == OuterViewportScrollLayer())
2711         continue;
2712       else
2713         break;
2714     }
2715
2716     did_lock_scrolling_layer_ = true;
2717     if (!should_bubble_scrolls_) {
2718       active_tree_->SetCurrentlyScrollingLayer(layer_impl);
2719       break;
2720     }
2721
2722     // If the applied delta is within 45 degrees of the input delta, bail out to
2723     // make it easier to scroll just one layer in one direction without
2724     // affecting any of its parents.
2725     float angle_threshold = 45;
2726     if (MathUtil::SmallestAngleBetweenVectors(
2727             applied_delta, pending_delta) < angle_threshold) {
2728       pending_delta = gfx::Vector2dF();
2729       break;
2730     }
2731
2732     // Allow further movement only on an axis perpendicular to the direction in
2733     // which the layer moved.
2734     gfx::Vector2dF perpendicular_axis(-applied_delta.y(), applied_delta.x());
2735     pending_delta = MathUtil::ProjectVector(pending_delta, perpendicular_axis);
2736
2737     if (gfx::ToRoundedVector2d(pending_delta).IsZero())
2738       break;
2739   }
2740
2741   bool did_scroll_content = did_scroll_x || did_scroll_y;
2742   if (did_scroll_content) {
2743     // If we are scrolling with an active scroll handler, forward latency
2744     // tracking information to the main thread so the delay introduced by the
2745     // handler is accounted for.
2746     if (scroll_affects_scroll_handler())
2747       NotifySwapPromiseMonitorsOfForwardingToMainThread();
2748     client_->SetNeedsCommitOnImplThread();
2749     SetNeedsRedraw();
2750     client_->RenewTreePriority();
2751   }
2752
2753   // Scrolling along an axis resets accumulated root overscroll for that axis.
2754   if (did_scroll_x)
2755     accumulated_root_overscroll_.set_x(0);
2756   if (did_scroll_y)
2757     accumulated_root_overscroll_.set_y(0);
2758
2759   accumulated_root_overscroll_ += unused_root_delta;
2760   bool did_overscroll = !unused_root_delta.IsZero();
2761   if (did_overscroll && input_handler_client_) {
2762     input_handler_client_->DidOverscroll(
2763         viewport_point, accumulated_root_overscroll_, unused_root_delta);
2764   }
2765
2766   return did_scroll_content || did_scroll_top_controls;
2767 }
2768
2769 // This implements scrolling by page as described here:
2770 // http://msdn.microsoft.com/en-us/library/windows/desktop/ms645601(v=vs.85).aspx#_win32_The_Mouse_Wheel
2771 // for events with WHEEL_PAGESCROLL set.
2772 bool LayerTreeHostImpl::ScrollVerticallyByPage(const gfx::Point& viewport_point,
2773                                                ScrollDirection direction) {
2774   DCHECK(wheel_scrolling_);
2775
2776   for (LayerImpl* layer_impl = CurrentlyScrollingLayer();
2777        layer_impl;
2778        layer_impl = layer_impl->parent()) {
2779     if (!layer_impl->scrollable())
2780       continue;
2781
2782     if (!layer_impl->HasScrollbar(VERTICAL))
2783       continue;
2784
2785     float height = layer_impl->clip_height();
2786
2787     // These magical values match WebKit and are designed to scroll nearly the
2788     // entire visible content height but leave a bit of overlap.
2789     float page = std::max(height * 0.875f, 1.f);
2790     if (direction == SCROLL_BACKWARD)
2791       page = -page;
2792
2793     gfx::Vector2dF delta = gfx::Vector2dF(0.f, page);
2794
2795     gfx::Vector2dF applied_delta = ScrollLayerWithLocalDelta(layer_impl, delta);
2796
2797     if (!applied_delta.IsZero()) {
2798       client_->SetNeedsCommitOnImplThread();
2799       SetNeedsRedraw();
2800       client_->RenewTreePriority();
2801       return true;
2802     }
2803
2804     active_tree_->SetCurrentlyScrollingLayer(layer_impl);
2805   }
2806
2807   return false;
2808 }
2809
2810 void LayerTreeHostImpl::SetRootLayerScrollOffsetDelegate(
2811       LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate) {
2812   root_layer_scroll_offset_delegate_ = root_layer_scroll_offset_delegate;
2813   active_tree_->SetRootLayerScrollOffsetDelegate(
2814       root_layer_scroll_offset_delegate_);
2815 }
2816
2817 void LayerTreeHostImpl::OnRootLayerDelegatedScrollOffsetChanged() {
2818   DCHECK(root_layer_scroll_offset_delegate_);
2819   client_->SetNeedsCommitOnImplThread();
2820   SetNeedsRedraw();
2821   active_tree_->OnRootLayerDelegatedScrollOffsetChanged();
2822   active_tree_->set_needs_update_draw_properties();
2823 }
2824
2825 void LayerTreeHostImpl::ClearCurrentlyScrollingLayer() {
2826   active_tree_->ClearCurrentlyScrollingLayer();
2827   did_lock_scrolling_layer_ = false;
2828   scroll_affects_scroll_handler_ = false;
2829   accumulated_root_overscroll_ = gfx::Vector2dF();
2830 }
2831
2832 void LayerTreeHostImpl::ScrollEnd() {
2833   if (top_controls_manager_)
2834     top_controls_manager_->ScrollEnd();
2835   ClearCurrentlyScrollingLayer();
2836 }
2837
2838 InputHandler::ScrollStatus LayerTreeHostImpl::FlingScrollBegin() {
2839   if (!active_tree_->CurrentlyScrollingLayer())
2840     return ScrollIgnored;
2841
2842   if (settings_.ignore_root_layer_flings &&
2843       (active_tree_->CurrentlyScrollingLayer() == InnerViewportScrollLayer() ||
2844        active_tree_->CurrentlyScrollingLayer() == OuterViewportScrollLayer())) {
2845     ClearCurrentlyScrollingLayer();
2846     return ScrollIgnored;
2847   }
2848
2849   if (!wheel_scrolling_) {
2850     // Allow the fling to lock to the first layer that moves after the initial
2851     // fling |ScrollBy()| event.
2852     did_lock_scrolling_layer_ = false;
2853     should_bubble_scrolls_ = false;
2854   }
2855
2856   return ScrollStarted;
2857 }
2858
2859 float LayerTreeHostImpl::DeviceSpaceDistanceToLayer(
2860     const gfx::PointF& device_viewport_point,
2861     LayerImpl* layer_impl) {
2862   if (!layer_impl)
2863     return std::numeric_limits<float>::max();
2864
2865   gfx::Rect layer_impl_bounds(
2866       layer_impl->content_bounds());
2867
2868   gfx::RectF device_viewport_layer_impl_bounds = MathUtil::MapClippedRect(
2869       layer_impl->screen_space_transform(),
2870       layer_impl_bounds);
2871
2872   return device_viewport_layer_impl_bounds.ManhattanDistanceToPoint(
2873       device_viewport_point);
2874 }
2875
2876 void LayerTreeHostImpl::MouseMoveAt(const gfx::Point& viewport_point) {
2877   gfx::PointF device_viewport_point = gfx::ScalePoint(viewport_point,
2878                                                       device_scale_factor_);
2879   LayerImpl* layer_impl =
2880       active_tree_->FindLayerThatIsHitByPoint(device_viewport_point);
2881   if (HandleMouseOverScrollbar(layer_impl, device_viewport_point))
2882     return;
2883
2884   if (scroll_layer_id_when_mouse_over_scrollbar_) {
2885     LayerImpl* scroll_layer_impl = active_tree_->LayerById(
2886         scroll_layer_id_when_mouse_over_scrollbar_);
2887
2888     // The check for a null scroll_layer_impl below was added to see if it will
2889     // eliminate the crashes described in http://crbug.com/326635.
2890     // TODO(wjmaclean) Add a unit test if this fixes the crashes.
2891     ScrollbarAnimationController* animation_controller =
2892         scroll_layer_impl ? scroll_layer_impl->scrollbar_animation_controller()
2893                           : NULL;
2894     if (animation_controller)
2895       animation_controller->DidMouseMoveOffScrollbar();
2896     scroll_layer_id_when_mouse_over_scrollbar_ = 0;
2897   }
2898
2899   bool scroll_on_main_thread = false;
2900   LayerImpl* scroll_layer_impl =
2901       FindScrollLayerForDeviceViewportPoint(device_viewport_point,
2902                                             InputHandler::Gesture,
2903                                             layer_impl,
2904                                             &scroll_on_main_thread,
2905                                             NULL);
2906   if (scroll_on_main_thread || !scroll_layer_impl)
2907     return;
2908
2909   ScrollbarAnimationController* animation_controller =
2910       scroll_layer_impl->scrollbar_animation_controller();
2911   if (!animation_controller)
2912     return;
2913
2914   // TODO(wjmaclean) Is it ok to choose distance from more than two scrollbars?
2915   float distance_to_scrollbar = std::numeric_limits<float>::max();
2916   for (LayerImpl::ScrollbarSet::iterator it =
2917            scroll_layer_impl->scrollbars()->begin();
2918        it != scroll_layer_impl->scrollbars()->end();
2919        ++it)
2920     distance_to_scrollbar =
2921         std::min(distance_to_scrollbar,
2922                  DeviceSpaceDistanceToLayer(device_viewport_point, *it));
2923
2924   animation_controller->DidMouseMoveNear(distance_to_scrollbar /
2925                                          device_scale_factor_);
2926 }
2927
2928 bool LayerTreeHostImpl::HandleMouseOverScrollbar(LayerImpl* layer_impl,
2929     const gfx::PointF& device_viewport_point) {
2930   if (layer_impl && layer_impl->ToScrollbarLayer()) {
2931     int scroll_layer_id = layer_impl->ToScrollbarLayer()->ScrollLayerId();
2932     layer_impl = active_tree_->LayerById(scroll_layer_id);
2933     if (layer_impl && layer_impl->scrollbar_animation_controller()) {
2934       scroll_layer_id_when_mouse_over_scrollbar_ = scroll_layer_id;
2935       layer_impl->scrollbar_animation_controller()->DidMouseMoveNear(0);
2936     } else {
2937       scroll_layer_id_when_mouse_over_scrollbar_ = 0;
2938     }
2939
2940     return true;
2941   }
2942
2943   return false;
2944 }
2945
2946 void LayerTreeHostImpl::PinchGestureBegin() {
2947   pinch_gesture_active_ = true;
2948   previous_pinch_anchor_ = gfx::Point();
2949   client_->RenewTreePriority();
2950   pinch_gesture_end_should_clear_scrolling_layer_ = !CurrentlyScrollingLayer();
2951   if (active_tree_->OuterViewportScrollLayer()) {
2952     active_tree_->SetCurrentlyScrollingLayer(
2953         active_tree_->OuterViewportScrollLayer());
2954   } else {
2955     active_tree_->SetCurrentlyScrollingLayer(
2956         active_tree_->InnerViewportScrollLayer());
2957   }
2958   if (top_controls_manager_)
2959     top_controls_manager_->PinchBegin();
2960 }
2961
2962 void LayerTreeHostImpl::PinchGestureUpdate(float magnify_delta,
2963                                            const gfx::Point& anchor) {
2964   if (!InnerViewportScrollLayer())
2965     return;
2966
2967   TRACE_EVENT0("cc", "LayerTreeHostImpl::PinchGestureUpdate");
2968
2969   // For a moment the scroll offset ends up being outside of the max range. This
2970   // confuses the delegate so we switch it off till after we're done processing
2971   // the pinch update.
2972   active_tree_->SetRootLayerScrollOffsetDelegate(NULL);
2973
2974   // Keep the center-of-pinch anchor specified by (x, y) in a stable
2975   // position over the course of the magnify.
2976   float page_scale_delta = active_tree_->page_scale_delta();
2977   gfx::PointF previous_scale_anchor =
2978       gfx::ScalePoint(anchor, 1.f / page_scale_delta);
2979   active_tree_->SetPageScaleDelta(page_scale_delta * magnify_delta);
2980   page_scale_delta = active_tree_->page_scale_delta();
2981   gfx::PointF new_scale_anchor =
2982       gfx::ScalePoint(anchor, 1.f / page_scale_delta);
2983   gfx::Vector2dF move = previous_scale_anchor - new_scale_anchor;
2984
2985   previous_pinch_anchor_ = anchor;
2986
2987   move.Scale(1 / active_tree_->page_scale_factor());
2988   // If clamping the inner viewport scroll offset causes a change, it should
2989   // be accounted for from the intended move.
2990   move -= InnerViewportScrollLayer()->ClampScrollToMaxScrollOffset();
2991
2992   // We manually manage the bubbling behaviour here as it is different to that
2993   // implemented in LayerTreeHostImpl::ScrollBy(). Specifically:
2994   // 1) we want to explicit limit the bubbling to the outer/inner viewports,
2995   // 2) we don't want the directional limitations on the unused parts that
2996   //    ScrollBy() implements, and
2997   // 3) pinching should not engage the top controls manager.
2998   gfx::Vector2dF unused = OuterViewportScrollLayer()
2999                               ? OuterViewportScrollLayer()->ScrollBy(move)
3000                               : move;
3001
3002   if (!unused.IsZero()) {
3003     InnerViewportScrollLayer()->ScrollBy(unused);
3004     InnerViewportScrollLayer()->ClampScrollToMaxScrollOffset();
3005   }
3006
3007   active_tree_->SetRootLayerScrollOffsetDelegate(
3008       root_layer_scroll_offset_delegate_);
3009
3010   client_->SetNeedsCommitOnImplThread();
3011   SetNeedsRedraw();
3012   client_->RenewTreePriority();
3013 }
3014
3015 void LayerTreeHostImpl::PinchGestureEnd() {
3016   pinch_gesture_active_ = false;
3017   if (pinch_gesture_end_should_clear_scrolling_layer_) {
3018     pinch_gesture_end_should_clear_scrolling_layer_ = false;
3019     ClearCurrentlyScrollingLayer();
3020   }
3021   if (top_controls_manager_)
3022     top_controls_manager_->PinchEnd();
3023   client_->SetNeedsCommitOnImplThread();
3024   // When a pinch ends, we may be displaying content cached at incorrect scales,
3025   // so updating draw properties and drawing will ensure we are using the right
3026   // scales that we want when we're not inside a pinch.
3027   active_tree_->set_needs_update_draw_properties();
3028   SetNeedsRedraw();
3029   // TODO(danakj): Don't set root damage. Just updating draw properties and
3030   // getting new tiles rastered should be enough! crbug.com/427423
3031   SetFullRootLayerDamage();
3032 }
3033
3034 static void CollectScrollDeltas(ScrollAndScaleSet* scroll_info,
3035                                 LayerImpl* layer_impl) {
3036   if (!layer_impl)
3037     return;
3038
3039   gfx::Vector2d scroll_delta =
3040       gfx::ToFlooredVector2d(layer_impl->ScrollDelta());
3041   if (!scroll_delta.IsZero()) {
3042     LayerTreeHostCommon::ScrollUpdateInfo scroll;
3043     scroll.layer_id = layer_impl->id();
3044     scroll.scroll_delta = scroll_delta;
3045     scroll_info->scrolls.push_back(scroll);
3046     layer_impl->SetSentScrollDelta(scroll_delta);
3047   }
3048
3049   for (size_t i = 0; i < layer_impl->children().size(); ++i)
3050     CollectScrollDeltas(scroll_info, layer_impl->children()[i]);
3051 }
3052
3053 scoped_ptr<ScrollAndScaleSet> LayerTreeHostImpl::ProcessScrollDeltas() {
3054   scoped_ptr<ScrollAndScaleSet> scroll_info(new ScrollAndScaleSet());
3055
3056   CollectScrollDeltas(scroll_info.get(), active_tree_->root_layer());
3057   scroll_info->page_scale_delta = active_tree_->page_scale_delta();
3058   active_tree_->set_sent_page_scale_delta(scroll_info->page_scale_delta);
3059   scroll_info->swap_promises.swap(swap_promises_for_main_thread_scroll_update_);
3060   scroll_info->top_controls_delta = active_tree()->top_controls_delta();
3061   active_tree_->set_sent_top_controls_delta(scroll_info->top_controls_delta);
3062
3063   return scroll_info.Pass();
3064 }
3065
3066 void LayerTreeHostImpl::SetFullRootLayerDamage() {
3067   SetViewportDamage(gfx::Rect(DrawViewportSize()));
3068 }
3069
3070 void LayerTreeHostImpl::ScrollViewportInnerFirst(gfx::Vector2dF scroll_delta) {
3071   DCHECK(InnerViewportScrollLayer());
3072   LayerImpl* scroll_layer = InnerViewportScrollLayer();
3073
3074   gfx::Vector2dF unused_delta = scroll_layer->ScrollBy(scroll_delta);
3075   if (!unused_delta.IsZero() && OuterViewportScrollLayer())
3076     OuterViewportScrollLayer()->ScrollBy(unused_delta);
3077 }
3078
3079 void LayerTreeHostImpl::ScrollViewportBy(gfx::Vector2dF scroll_delta) {
3080   DCHECK(InnerViewportScrollLayer());
3081   LayerImpl* scroll_layer = OuterViewportScrollLayer()
3082                                 ? OuterViewportScrollLayer()
3083                                 : InnerViewportScrollLayer();
3084
3085   gfx::Vector2dF unused_delta = scroll_layer->ScrollBy(scroll_delta);
3086
3087   if (!unused_delta.IsZero() && (scroll_layer == OuterViewportScrollLayer()))
3088     InnerViewportScrollLayer()->ScrollBy(unused_delta);
3089 }
3090
3091 void LayerTreeHostImpl::AnimatePageScale(base::TimeTicks monotonic_time) {
3092   if (!page_scale_animation_)
3093     return;
3094
3095   gfx::ScrollOffset scroll_total = active_tree_->TotalScrollOffset();
3096
3097   if (!page_scale_animation_->IsAnimationStarted())
3098     page_scale_animation_->StartAnimation(monotonic_time);
3099
3100   active_tree_->SetPageScaleDelta(
3101       page_scale_animation_->PageScaleFactorAtTime(monotonic_time) /
3102       active_tree_->page_scale_factor());
3103   gfx::ScrollOffset next_scroll = gfx::ScrollOffset(
3104       page_scale_animation_->ScrollOffsetAtTime(monotonic_time));
3105
3106   ScrollViewportInnerFirst(next_scroll.DeltaFrom(scroll_total));
3107   SetNeedsRedraw();
3108
3109   if (page_scale_animation_->IsAnimationCompleteAtTime(monotonic_time)) {
3110     page_scale_animation_ = nullptr;
3111     client_->SetNeedsCommitOnImplThread();
3112     client_->RenewTreePriority();
3113   } else {
3114     SetNeedsAnimate();
3115   }
3116 }
3117
3118 void LayerTreeHostImpl::AnimateTopControls(base::TimeTicks time) {
3119   if (!top_controls_manager_ || !top_controls_manager_->animation())
3120     return;
3121
3122   gfx::Vector2dF scroll = top_controls_manager_->Animate(time);
3123
3124   if (top_controls_manager_->animation())
3125     SetNeedsAnimate();
3126
3127   if (active_tree_->TotalScrollOffset().y() == 0.f)
3128     return;
3129
3130   if (scroll.IsZero())
3131     return;
3132
3133   ScrollViewportBy(gfx::ScaleVector2d(
3134       scroll, 1.f / active_tree_->total_page_scale_factor()));
3135   SetNeedsRedraw();
3136   client_->SetNeedsCommitOnImplThread();
3137   client_->RenewTreePriority();
3138 }
3139
3140 void LayerTreeHostImpl::AnimateLayers(base::TimeTicks monotonic_time) {
3141   if (!settings_.accelerated_animation_enabled ||
3142       !needs_animate_layers() ||
3143       !active_tree_->root_layer())
3144     return;
3145
3146   TRACE_EVENT0("cc", "LayerTreeHostImpl::AnimateLayers");
3147   AnimationRegistrar::AnimationControllerMap copy =
3148       animation_registrar_->active_animation_controllers();
3149   for (AnimationRegistrar::AnimationControllerMap::iterator iter = copy.begin();
3150        iter != copy.end();
3151        ++iter)
3152     (*iter).second->Animate(monotonic_time);
3153
3154   SetNeedsAnimate();
3155 }
3156
3157 void LayerTreeHostImpl::UpdateAnimationState(bool start_ready_animations) {
3158   if (!settings_.accelerated_animation_enabled ||
3159       !needs_animate_layers() ||
3160       !active_tree_->root_layer())
3161     return;
3162
3163   TRACE_EVENT0("cc", "LayerTreeHostImpl::UpdateAnimationState");
3164   scoped_ptr<AnimationEventsVector> events =
3165       make_scoped_ptr(new AnimationEventsVector);
3166   AnimationRegistrar::AnimationControllerMap copy =
3167       animation_registrar_->active_animation_controllers();
3168   for (AnimationRegistrar::AnimationControllerMap::iterator iter = copy.begin();
3169        iter != copy.end();
3170        ++iter)
3171     (*iter).second->UpdateState(start_ready_animations, events.get());
3172
3173   if (!events->empty()) {
3174     client_->PostAnimationEventsToMainThreadOnImplThread(events.Pass());
3175   }
3176
3177   SetNeedsAnimate();
3178 }
3179
3180 void LayerTreeHostImpl::ActivateAnimations() {
3181   if (!settings_.accelerated_animation_enabled || !needs_animate_layers() ||
3182       !active_tree_->root_layer())
3183     return;
3184
3185   TRACE_EVENT0("cc", "LayerTreeHostImpl::ActivateAnimations");
3186   AnimationRegistrar::AnimationControllerMap copy =
3187       animation_registrar_->active_animation_controllers();
3188   for (AnimationRegistrar::AnimationControllerMap::iterator iter = copy.begin();
3189        iter != copy.end();
3190        ++iter)
3191     (*iter).second->ActivateAnimations();
3192 }
3193
3194 base::TimeDelta LayerTreeHostImpl::LowFrequencyAnimationInterval() const {
3195   return base::TimeDelta::FromSeconds(1);
3196 }
3197
3198 std::string LayerTreeHostImpl::LayerTreeAsJson() const {
3199   std::string str;
3200   if (active_tree_->root_layer()) {
3201     scoped_ptr<base::Value> json(active_tree_->root_layer()->LayerTreeAsJson());
3202     base::JSONWriter::WriteWithOptions(
3203         json.get(), base::JSONWriter::OPTIONS_PRETTY_PRINT, &str);
3204   }
3205   return str;
3206 }
3207
3208 int LayerTreeHostImpl::SourceAnimationFrameNumber() const {
3209   return fps_counter_->current_frame_number();
3210 }
3211
3212 void LayerTreeHostImpl::AnimateScrollbars(base::TimeTicks time) {
3213   AnimateScrollbarsRecursive(active_tree_->root_layer(), time);
3214 }
3215
3216 void LayerTreeHostImpl::AnimateScrollbarsRecursive(LayerImpl* layer,
3217                                                    base::TimeTicks time) {
3218   if (!layer)
3219     return;
3220
3221   ScrollbarAnimationController* scrollbar_controller =
3222       layer->scrollbar_animation_controller();
3223   if (scrollbar_controller)
3224     scrollbar_controller->Animate(time);
3225
3226   for (size_t i = 0; i < layer->children().size(); ++i)
3227     AnimateScrollbarsRecursive(layer->children()[i], time);
3228 }
3229
3230 void LayerTreeHostImpl::PostDelayedScrollbarFade(
3231     const base::Closure& start_fade,
3232     base::TimeDelta delay) {
3233   client_->PostDelayedScrollbarFadeOnImplThread(start_fade, delay);
3234 }
3235
3236 void LayerTreeHostImpl::SetNeedsScrollbarAnimationFrame() {
3237   TRACE_EVENT_INSTANT0(
3238       "cc",
3239       "LayerTreeHostImpl::SetNeedsRedraw due to scrollbar fade",
3240       TRACE_EVENT_SCOPE_THREAD);
3241   SetNeedsAnimate();
3242 }
3243
3244 void LayerTreeHostImpl::SetTreePriority(TreePriority priority) {
3245   if (!tile_manager_)
3246     return;
3247
3248   if (global_tile_state_.tree_priority == priority)
3249     return;
3250   global_tile_state_.tree_priority = priority;
3251   DidModifyTilePriorities();
3252 }
3253
3254 TreePriority LayerTreeHostImpl::GetTreePriority() const {
3255   return global_tile_state_.tree_priority;
3256 }
3257
3258 void LayerTreeHostImpl::UpdateCurrentBeginFrameArgs(
3259     const BeginFrameArgs& args) {
3260   DCHECK(!current_begin_frame_args_.IsValid());
3261   current_begin_frame_args_ = args;
3262   // TODO(skyostil): Stop overriding the frame time once the usage of frame
3263   // timing is unified.
3264   current_begin_frame_args_.frame_time = gfx::FrameTime::Now();
3265 }
3266
3267 void LayerTreeHostImpl::ResetCurrentBeginFrameArgsForNextFrame() {
3268   current_begin_frame_args_ = BeginFrameArgs();
3269 }
3270
3271 BeginFrameArgs LayerTreeHostImpl::CurrentBeginFrameArgs() const {
3272   // Try to use the current frame time to keep animations non-jittery.  But if
3273   // we're not in a frame (because this is during an input event or a delayed
3274   // task), fall back to physical time.  This should still be monotonic.
3275   if (current_begin_frame_args_.IsValid())
3276     return current_begin_frame_args_;
3277   return BeginFrameArgs::Create(gfx::FrameTime::Now(),
3278                                 base::TimeTicks(),
3279                                 BeginFrameArgs::DefaultInterval());
3280 }
3281
3282 void LayerTreeHostImpl::AsValueInto(base::debug::TracedValue* value) const {
3283   return AsValueWithFrameInto(NULL, value);
3284 }
3285
3286 scoped_refptr<base::debug::ConvertableToTraceFormat>
3287 LayerTreeHostImpl::AsValue() const {
3288   return AsValueWithFrame(NULL);
3289 }
3290
3291 scoped_refptr<base::debug::ConvertableToTraceFormat>
3292 LayerTreeHostImpl::AsValueWithFrame(FrameData* frame) const {
3293   scoped_refptr<base::debug::TracedValue> state =
3294       new base::debug::TracedValue();
3295   AsValueWithFrameInto(frame, state.get());
3296   return state;
3297 }
3298
3299 void LayerTreeHostImpl::AsValueWithFrameInto(
3300     FrameData* frame,
3301     base::debug::TracedValue* state) const {
3302   if (this->pending_tree_) {
3303     state->BeginDictionary("activation_state");
3304     ActivationStateAsValueInto(state);
3305     state->EndDictionary();
3306   }
3307   state->BeginDictionary("device_viewport_size");
3308   MathUtil::AddToTracedValue(device_viewport_size_, state);
3309   state->EndDictionary();
3310
3311   std::set<const Tile*> tiles;
3312   active_tree_->GetAllTilesForTracing(&tiles);
3313   if (pending_tree_)
3314     pending_tree_->GetAllTilesForTracing(&tiles);
3315
3316   state->BeginArray("active_tiles");
3317   for (std::set<const Tile*>::const_iterator it = tiles.begin();
3318        it != tiles.end();
3319        ++it) {
3320     const Tile* tile = *it;
3321
3322     state->BeginDictionary();
3323     tile->AsValueInto(state);
3324     state->EndDictionary();
3325   }
3326   state->EndArray();
3327
3328   if (tile_manager_) {
3329     state->BeginDictionary("tile_manager_basic_state");
3330     tile_manager_->BasicStateAsValueInto(state);
3331     state->EndDictionary();
3332   }
3333   state->BeginDictionary("active_tree");
3334   active_tree_->AsValueInto(state);
3335   state->EndDictionary();
3336   if (pending_tree_) {
3337     state->BeginDictionary("pending_tree");
3338     pending_tree_->AsValueInto(state);
3339     state->EndDictionary();
3340   }
3341   if (frame) {
3342     state->BeginDictionary("frame");
3343     frame->AsValueInto(state);
3344     state->EndDictionary();
3345   }
3346 }
3347
3348 scoped_refptr<base::debug::ConvertableToTraceFormat>
3349 LayerTreeHostImpl::ActivationStateAsValue() const {
3350   scoped_refptr<base::debug::TracedValue> state =
3351       new base::debug::TracedValue();
3352   ActivationStateAsValueInto(state.get());
3353   return state;
3354 }
3355
3356 void LayerTreeHostImpl::ActivationStateAsValueInto(
3357     base::debug::TracedValue* state) const {
3358   TracedValue::SetIDRef(this, state, "lthi");
3359   if (tile_manager_) {
3360     state->BeginDictionary("tile_manager");
3361     tile_manager_->BasicStateAsValueInto(state);
3362     state->EndDictionary();
3363   }
3364 }
3365
3366 void LayerTreeHostImpl::SetDebugState(
3367     const LayerTreeDebugState& new_debug_state) {
3368   if (LayerTreeDebugState::Equal(debug_state_, new_debug_state))
3369     return;
3370   if (debug_state_.continuous_painting != new_debug_state.continuous_painting)
3371     paint_time_counter_->ClearHistory();
3372
3373   debug_state_ = new_debug_state;
3374   UpdateTileManagerMemoryPolicy(ActualManagedMemoryPolicy());
3375   SetFullRootLayerDamage();
3376 }
3377
3378 void LayerTreeHostImpl::CreateUIResource(UIResourceId uid,
3379                                          const UIResourceBitmap& bitmap) {
3380   DCHECK_GT(uid, 0);
3381
3382   GLint wrap_mode = 0;
3383   switch (bitmap.GetWrapMode()) {
3384     case UIResourceBitmap::CLAMP_TO_EDGE:
3385       wrap_mode = GL_CLAMP_TO_EDGE;
3386       break;
3387     case UIResourceBitmap::REPEAT:
3388       wrap_mode = GL_REPEAT;
3389       break;
3390   }
3391
3392   // Allow for multiple creation requests with the same UIResourceId.  The
3393   // previous resource is simply deleted.
3394   ResourceProvider::ResourceId id = ResourceIdForUIResource(uid);
3395   if (id)
3396     DeleteUIResource(uid);
3397
3398   ResourceFormat format = resource_provider_->best_texture_format();
3399   switch (bitmap.GetFormat()) {
3400     case UIResourceBitmap::RGBA8:
3401       break;
3402     case UIResourceBitmap::ALPHA_8:
3403       format = ALPHA_8;
3404       break;
3405     case UIResourceBitmap::ETC1:
3406       format = ETC1;
3407       break;
3408   }
3409   id =
3410       resource_provider_->CreateResource(bitmap.GetSize(),
3411                                          wrap_mode,
3412                                          ResourceProvider::TextureHintImmutable,
3413                                          format);
3414
3415   UIResourceData data;
3416   data.resource_id = id;
3417   data.size = bitmap.GetSize();
3418   data.opaque = bitmap.GetOpaque();
3419
3420   ui_resource_map_[uid] = data;
3421
3422   AutoLockUIResourceBitmap bitmap_lock(bitmap);
3423   resource_provider_->SetPixels(id,
3424                                 bitmap_lock.GetPixels(),
3425                                 gfx::Rect(bitmap.GetSize()),
3426                                 gfx::Rect(bitmap.GetSize()),
3427                                 gfx::Vector2d(0, 0));
3428   MarkUIResourceNotEvicted(uid);
3429 }
3430
3431 void LayerTreeHostImpl::DeleteUIResource(UIResourceId uid) {
3432   ResourceProvider::ResourceId id = ResourceIdForUIResource(uid);
3433   if (id) {
3434     resource_provider_->DeleteResource(id);
3435     ui_resource_map_.erase(uid);
3436   }
3437   MarkUIResourceNotEvicted(uid);
3438 }
3439
3440 void LayerTreeHostImpl::EvictAllUIResources() {
3441   if (ui_resource_map_.empty())
3442     return;
3443
3444   for (UIResourceMap::const_iterator iter = ui_resource_map_.begin();
3445       iter != ui_resource_map_.end();
3446       ++iter) {
3447     evicted_ui_resources_.insert(iter->first);
3448     resource_provider_->DeleteResource(iter->second.resource_id);
3449   }
3450   ui_resource_map_.clear();
3451
3452   client_->SetNeedsCommitOnImplThread();
3453   client_->OnCanDrawStateChanged(CanDraw());
3454   client_->RenewTreePriority();
3455 }
3456
3457 ResourceProvider::ResourceId LayerTreeHostImpl::ResourceIdForUIResource(
3458     UIResourceId uid) const {
3459   UIResourceMap::const_iterator iter = ui_resource_map_.find(uid);
3460   if (iter != ui_resource_map_.end())
3461     return iter->second.resource_id;
3462   return 0;
3463 }
3464
3465 bool LayerTreeHostImpl::IsUIResourceOpaque(UIResourceId uid) const {
3466   UIResourceMap::const_iterator iter = ui_resource_map_.find(uid);
3467   DCHECK(iter != ui_resource_map_.end());
3468   return iter->second.opaque;
3469 }
3470
3471 bool LayerTreeHostImpl::EvictedUIResourcesExist() const {
3472   return !evicted_ui_resources_.empty();
3473 }
3474
3475 void LayerTreeHostImpl::MarkUIResourceNotEvicted(UIResourceId uid) {
3476   std::set<UIResourceId>::iterator found_in_evicted =
3477       evicted_ui_resources_.find(uid);
3478   if (found_in_evicted == evicted_ui_resources_.end())
3479     return;
3480   evicted_ui_resources_.erase(found_in_evicted);
3481   if (evicted_ui_resources_.empty())
3482     client_->OnCanDrawStateChanged(CanDraw());
3483 }
3484
3485 void LayerTreeHostImpl::ScheduleMicroBenchmark(
3486     scoped_ptr<MicroBenchmarkImpl> benchmark) {
3487   micro_benchmark_controller_.ScheduleRun(benchmark.Pass());
3488 }
3489
3490 void LayerTreeHostImpl::InsertSwapPromiseMonitor(SwapPromiseMonitor* monitor) {
3491   swap_promise_monitor_.insert(monitor);
3492 }
3493
3494 void LayerTreeHostImpl::RemoveSwapPromiseMonitor(SwapPromiseMonitor* monitor) {
3495   swap_promise_monitor_.erase(monitor);
3496 }
3497
3498 void LayerTreeHostImpl::NotifySwapPromiseMonitorsOfSetNeedsRedraw() {
3499   std::set<SwapPromiseMonitor*>::iterator it = swap_promise_monitor_.begin();
3500   for (; it != swap_promise_monitor_.end(); it++)
3501     (*it)->OnSetNeedsRedrawOnImpl();
3502 }
3503
3504 void LayerTreeHostImpl::NotifySwapPromiseMonitorsOfForwardingToMainThread() {
3505   std::set<SwapPromiseMonitor*>::iterator it = swap_promise_monitor_.begin();
3506   for (; it != swap_promise_monitor_.end(); it++)
3507     (*it)->OnForwardScrollUpdateToMainThreadOnImpl();
3508 }
3509
3510 void LayerTreeHostImpl::RegisterPictureLayerImpl(PictureLayerImpl* layer) {
3511   DCHECK(std::find(picture_layers_.begin(), picture_layers_.end(), layer) ==
3512          picture_layers_.end());
3513   picture_layers_.push_back(layer);
3514 }
3515
3516 void LayerTreeHostImpl::UnregisterPictureLayerImpl(PictureLayerImpl* layer) {
3517   std::vector<PictureLayerImpl*>::iterator it =
3518       std::find(picture_layers_.begin(), picture_layers_.end(), layer);
3519   DCHECK(it != picture_layers_.end());
3520   picture_layers_.erase(it);
3521 }
3522
3523 }  // namespace cc