src/cc/trees/single_thread_proxy.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/single_thread_proxy.h"
   6
   7 #include "base/auto_reset.h"
   8 #include "base/debug/trace_event.h"
   9 #include "cc/debug/benchmark_instrumentation.h"
  10 #include "cc/output/context_provider.h"
  11 #include "cc/output/output_surface.h"
  12 #include "cc/quads/draw_quad.h"
  13 #include "cc/resources/prioritized_resource_manager.h"
  14 #include "cc/resources/resource_update_controller.h"
  15 #include "cc/trees/blocking_task_runner.h"
  16 #include "cc/trees/layer_tree_host.h"
  17 #include "cc/trees/layer_tree_host_single_thread_client.h"
  18 #include "cc/trees/layer_tree_impl.h"
  19 #include "ui/gfx/frame_time.h"
  20
  21 namespace cc {
  22
  23 scoped_ptr<Proxy> SingleThreadProxy::Create(
  24     LayerTreeHost* layer_tree_host,
  25     LayerTreeHostSingleThreadClient* client) {
  26   return make_scoped_ptr(
  27       new SingleThreadProxy(layer_tree_host, client)).PassAs<Proxy>();
  28 }
  29
  30 SingleThreadProxy::SingleThreadProxy(LayerTreeHost* layer_tree_host,
  31                                      LayerTreeHostSingleThreadClient* client)
  32     : Proxy(NULL),
  33       layer_tree_host_(layer_tree_host),
  34       client_(client),
  35       created_offscreen_context_provider_(false),
  36       next_frame_is_newly_committed_frame_(false),
  37       inside_draw_(false) {
  38   TRACE_EVENT0("cc", "SingleThreadProxy::SingleThreadProxy");
  39   DCHECK(Proxy::IsMainThread());
  40   DCHECK(layer_tree_host);
  41
  42   // Impl-side painting not supported without threaded compositing.
  43   CHECK(!layer_tree_host->settings().impl_side_painting)
  44       << "Threaded compositing must be enabled to use impl-side painting.";
  45 }
  46
  47 void SingleThreadProxy::Start() {
  48   DebugScopedSetImplThread impl(this);
  49   layer_tree_host_impl_ = layer_tree_host_->CreateLayerTreeHostImpl(this);
  50 }
  51
  52 SingleThreadProxy::~SingleThreadProxy() {
  53   TRACE_EVENT0("cc", "SingleThreadProxy::~SingleThreadProxy");
  54   DCHECK(Proxy::IsMainThread());
  55   // Make sure Stop() got called or never Started.
  56   DCHECK(!layer_tree_host_impl_);
  57 }
  58
  59 bool SingleThreadProxy::CompositeAndReadback(void* pixels,
  60                                              const gfx::Rect& rect) {
  61   TRACE_EVENT0("cc", "SingleThreadProxy::CompositeAndReadback");
  62   DCHECK(Proxy::IsMainThread());
  63
  64   gfx::Rect device_viewport_damage_rect = rect;
  65
  66   LayerTreeHostImpl::FrameData frame;
  67   if (!CommitAndComposite(gfx::FrameTime::Now(),
  68                           device_viewport_damage_rect,
  69                           true,  // for_readback
  70                           &frame))
  71     return false;
  72
  73   {
  74     DebugScopedSetImplThread impl(this);
  75     layer_tree_host_impl_->Readback(pixels, rect);
  76
  77     if (layer_tree_host_impl_->IsContextLost())
  78       return false;
  79   }
  80
  81   return true;
  82 }
  83
  84 void SingleThreadProxy::FinishAllRendering() {
  85   TRACE_EVENT0("cc", "SingleThreadProxy::FinishAllRendering");
  86   DCHECK(Proxy::IsMainThread());
  87   {
  88     DebugScopedSetImplThread impl(this);
  89     layer_tree_host_impl_->FinishAllRendering();
  90   }
  91 }
  92
  93 bool SingleThreadProxy::IsStarted() const {
  94   DCHECK(Proxy::IsMainThread());
  95   return layer_tree_host_impl_;
  96 }
  97
  98 void SingleThreadProxy::SetLayerTreeHostClientReady() {
  99   TRACE_EVENT0("cc", "SingleThreadProxy::SetLayerTreeHostClientReady");
 100   // Scheduling is controlled by the embedder in the single thread case, so
 101   // nothing to do.
 102 }
 103
 104 void SingleThreadProxy::SetVisible(bool visible) {
 105   TRACE_EVENT0("cc", "SingleThreadProxy::SetVisible");
 106   DebugScopedSetImplThread impl(this);
 107   layer_tree_host_impl_->SetVisible(visible);
 108
 109   // Changing visibility could change ShouldComposite().
 110   UpdateBackgroundAnimateTicking();
 111 }
 112
 113 void SingleThreadProxy::CreateAndInitializeOutputSurface() {
 114   TRACE_EVENT0(
 115       "cc", "SingleThreadProxy::CreateAndInitializeOutputSurface");
 116   DCHECK(Proxy::IsMainThread());
 117
 118   scoped_ptr<OutputSurface> output_surface =
 119       layer_tree_host_->CreateOutputSurface();
 120   if (!output_surface) {
 121     OnOutputSurfaceInitializeAttempted(false);
 122     return;
 123   }
 124
 125   scoped_refptr<ContextProvider> offscreen_context_provider;
 126   if (created_offscreen_context_provider_) {
 127     offscreen_context_provider =
 128         layer_tree_host_->client()->OffscreenContextProvider();
 129     if (!offscreen_context_provider.get() ||
 130         !offscreen_context_provider->BindToCurrentThread()) {
 131       OnOutputSurfaceInitializeAttempted(false);
 132       return;
 133     }
 134   }
 135
 136   {
 137     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
 138     DebugScopedSetImplThread impl(this);
 139     layer_tree_host_->DeleteContentsTexturesOnImplThread(
 140         layer_tree_host_impl_->resource_provider());
 141   }
 142
 143   bool initialized;
 144   {
 145     DebugScopedSetImplThread impl(this);
 146
 147     DCHECK(output_surface);
 148     initialized = layer_tree_host_impl_->InitializeRenderer(
 149         output_surface.Pass());
 150     if (!initialized && offscreen_context_provider.get()) {
 151       offscreen_context_provider->VerifyContexts();
 152       offscreen_context_provider = NULL;
 153     }
 154
 155     layer_tree_host_impl_->SetOffscreenContextProvider(
 156         offscreen_context_provider);
 157   }
 158
 159   OnOutputSurfaceInitializeAttempted(initialized);
 160 }
 161
 162 void SingleThreadProxy::OnOutputSurfaceInitializeAttempted(bool success) {
 163   LayerTreeHost::CreateResult result =
 164       layer_tree_host_->OnCreateAndInitializeOutputSurfaceAttempted(success);
 165   if (result == LayerTreeHost::CreateFailedButTryAgain) {
 166     // Force another recreation attempt to happen by requesting another commit.
 167     SetNeedsCommit();
 168   }
 169 }
 170
 171 const RendererCapabilities& SingleThreadProxy::GetRendererCapabilities() const {
 172   DCHECK(Proxy::IsMainThread());
 173   DCHECK(!layer_tree_host_->output_surface_lost());
 174   return renderer_capabilities_for_main_thread_;
 175 }
 176
 177 void SingleThreadProxy::SetNeedsAnimate() {
 178   TRACE_EVENT0("cc", "SingleThreadProxy::SetNeedsAnimate");
 179   DCHECK(Proxy::IsMainThread());
 180   client_->ScheduleAnimation();
 181 }
 182
 183 void SingleThreadProxy::SetNeedsUpdateLayers() {
 184   TRACE_EVENT0("cc", "SingleThreadProxy::SetNeedsUpdateLayers");
 185   DCHECK(Proxy::IsMainThread());
 186   client_->ScheduleComposite();
 187 }
 188
 189 void SingleThreadProxy::DoCommit(scoped_ptr<ResourceUpdateQueue> queue) {
 190   TRACE_EVENT0("cc", "SingleThreadProxy::DoCommit");
 191   DCHECK(Proxy::IsMainThread());
 192   // Commit immediately.
 193   {
 194     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
 195     DebugScopedSetImplThread impl(this);
 196
 197     // This CapturePostTasks should be destroyed before CommitComplete() is
 198     // called since that goes out to the embedder, and we want the embedder
 199     // to receive its callbacks before that.
 200     BlockingTaskRunner::CapturePostTasks blocked;
 201
 202     layer_tree_host_impl_->BeginCommit();
 203
 204     if (PrioritizedResourceManager* contents_texture_manager =
 205         layer_tree_host_->contents_texture_manager()) {
 206       contents_texture_manager->PushTexturePrioritiesToBackings();
 207     }
 208     layer_tree_host_->BeginCommitOnImplThread(layer_tree_host_impl_.get());
 209
 210     scoped_ptr<ResourceUpdateController> update_controller =
 211         ResourceUpdateController::Create(
 212             NULL,
 213             Proxy::MainThreadTaskRunner(),
 214             queue.Pass(),
 215             layer_tree_host_impl_->resource_provider());
 216     update_controller->Finalize();
 217
 218     if (layer_tree_host_impl_->EvictedUIResourcesExist())
 219       layer_tree_host_->RecreateUIResources();
 220
 221     layer_tree_host_->FinishCommitOnImplThread(layer_tree_host_impl_.get());
 222
 223     layer_tree_host_impl_->CommitComplete();
 224
 225 #ifndef NDEBUG
 226     // In the single-threaded case, the scale and scroll deltas should never be
 227     // touched on the impl layer tree.
 228     scoped_ptr<ScrollAndScaleSet> scroll_info =
 229         layer_tree_host_impl_->ProcessScrollDeltas();
 230     DCHECK(!scroll_info->scrolls.size());
 231     DCHECK_EQ(1.f, scroll_info->page_scale_delta);
 232 #endif
 233
 234     RenderingStatsInstrumentation* stats_instrumentation =
 235         layer_tree_host_->rendering_stats_instrumentation();
 236     BenchmarkInstrumentation::IssueMainThreadRenderingStatsEvent(
 237         stats_instrumentation->main_thread_rendering_stats());
 238     stats_instrumentation->AccumulateAndClearMainThreadStats();
 239   }
 240   layer_tree_host_->CommitComplete();
 241   next_frame_is_newly_committed_frame_ = true;
 242 }
 243
 244 void SingleThreadProxy::SetNeedsCommit() {
 245   DCHECK(Proxy::IsMainThread());
 246   client_->ScheduleComposite();
 247 }
 248
 249 void SingleThreadProxy::SetNeedsRedraw(const gfx::Rect& damage_rect) {
 250   TRACE_EVENT0("cc", "SingleThreadProxy::SetNeedsRedraw");
 251   SetNeedsRedrawRectOnImplThread(damage_rect);
 252   client_->ScheduleComposite();
 253 }
 254
 255 void SingleThreadProxy::SetNextCommitWaitsForActivation() {
 256   // There is no activation here other than commit. So do nothing.
 257 }
 258
 259 void SingleThreadProxy::SetDeferCommits(bool defer_commits) {
 260   // Thread-only feature.
 261   NOTREACHED();
 262 }
 263
 264 bool SingleThreadProxy::CommitRequested() const { return false; }
 265
 266 bool SingleThreadProxy::BeginMainFrameRequested() const { return false; }
 267
 268 size_t SingleThreadProxy::MaxPartialTextureUpdates() const {
 269   return std::numeric_limits<size_t>::max();
 270 }
 271
 272 void SingleThreadProxy::Stop() {
 273   TRACE_EVENT0("cc", "SingleThreadProxy::stop");
 274   DCHECK(Proxy::IsMainThread());
 275   {
 276     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
 277     DebugScopedSetImplThread impl(this);
 278
 279     layer_tree_host_->DeleteContentsTexturesOnImplThread(
 280         layer_tree_host_impl_->resource_provider());
 281     layer_tree_host_impl_.reset();
 282   }
 283   layer_tree_host_ = NULL;
 284 }
 285
 286 void SingleThreadProxy::OnCanDrawStateChanged(bool can_draw) {
 287   TRACE_EVENT1(
 288       "cc", "SingleThreadProxy::OnCanDrawStateChanged", "can_draw", can_draw);
 289   DCHECK(Proxy::IsImplThread());
 290   UpdateBackgroundAnimateTicking();
 291 }
 292
 293 void SingleThreadProxy::NotifyReadyToActivate() {
 294   // Thread-only feature.
 295   NOTREACHED();
 296 }
 297
 298 void SingleThreadProxy::SetNeedsRedrawOnImplThread() {
 299   client_->ScheduleComposite();
 300 }
 301
 302 void SingleThreadProxy::SetNeedsManageTilesOnImplThread() {
 303   // Thread-only/Impl-side-painting-only feature.
 304   NOTREACHED();
 305 }
 306
 307 void SingleThreadProxy::SetNeedsRedrawRectOnImplThread(
 308     const gfx::Rect& damage_rect) {
 309   // TODO(brianderson): Once we move render_widget scheduling into this class,
 310   // we can treat redraw requests more efficiently than CommitAndRedraw
 311   // requests.
 312   layer_tree_host_impl_->SetViewportDamage(damage_rect);
 313   SetNeedsCommit();
 314 }
 315
 316 void SingleThreadProxy::DidInitializeVisibleTileOnImplThread() {
 317   // Impl-side painting only.
 318   NOTREACHED();
 319 }
 320
 321 void SingleThreadProxy::SetNeedsCommitOnImplThread() {
 322   client_->ScheduleComposite();
 323 }
 324
 325 void SingleThreadProxy::PostAnimationEventsToMainThreadOnImplThread(
 326     scoped_ptr<AnimationEventsVector> events,
 327     base::Time wall_clock_time) {
 328   TRACE_EVENT0(
 329       "cc", "SingleThreadProxy::PostAnimationEventsToMainThreadOnImplThread");
 330   DCHECK(Proxy::IsImplThread());
 331   DebugScopedSetMainThread main(this);
 332   layer_tree_host_->SetAnimationEvents(events.Pass(), wall_clock_time);
 333 }
 334
 335 bool SingleThreadProxy::ReduceContentsTextureMemoryOnImplThread(
 336     size_t limit_bytes,
 337     int priority_cutoff) {
 338   DCHECK(IsImplThread());
 339   PrioritizedResourceManager* contents_texture_manager =
 340       layer_tree_host_->contents_texture_manager();
 341
 342   ResourceProvider* resource_provider =
 343       layer_tree_host_impl_->resource_provider();
 344
 345   if (!contents_texture_manager || !resource_provider)
 346     return false;
 347
 348   return contents_texture_manager->ReduceMemoryOnImplThread(
 349       limit_bytes, priority_cutoff, resource_provider);
 350 }
 351
 352 void SingleThreadProxy::SendManagedMemoryStats() {
 353   DCHECK(Proxy::IsImplThread());
 354   if (!layer_tree_host_impl_)
 355     return;
 356   PrioritizedResourceManager* contents_texture_manager =
 357       layer_tree_host_->contents_texture_manager();
 358   if (!contents_texture_manager)
 359     return;
 360
 361   layer_tree_host_impl_->SendManagedMemoryStats(
 362       contents_texture_manager->MemoryVisibleBytes(),
 363       contents_texture_manager->MemoryVisibleAndNearbyBytes(),
 364       contents_texture_manager->MemoryUseBytes());
 365 }
 366
 367 bool SingleThreadProxy::IsInsideDraw() { return inside_draw_; }
 368
 369 void SingleThreadProxy::UpdateRendererCapabilitiesOnImplThread() {
 370   DCHECK(IsImplThread());
 371   renderer_capabilities_for_main_thread_ =
 372       layer_tree_host_impl_->GetRendererCapabilities().MainThreadCapabilities();
 373 }
 374
 375 void SingleThreadProxy::DidLoseOutputSurfaceOnImplThread() {
 376   TRACE_EVENT0("cc", "SingleThreadProxy::DidLoseOutputSurfaceOnImplThread");
 377   // Cause a commit so we can notice the lost context.
 378   SetNeedsCommitOnImplThread();
 379   client_->DidAbortSwapBuffers();
 380 }
 381
 382 void SingleThreadProxy::DidSwapBuffersOnImplThread() {
 383   client_->DidPostSwapBuffers();
 384 }
 385
 386 void SingleThreadProxy::OnSwapBuffersCompleteOnImplThread() {
 387   TRACE_EVENT0("cc", "SingleThreadProxy::OnSwapBuffersCompleteOnImplThread");
 388   client_->DidCompleteSwapBuffers();
 389 }
 390
 391 // Called by the legacy scheduling path (e.g. where render_widget does the
 392 // scheduling)
 393 void SingleThreadProxy::CompositeImmediately(base::TimeTicks frame_begin_time) {
 394   TRACE_EVENT0("cc", "SingleThreadProxy::CompositeImmediately");
 395   gfx::Rect device_viewport_damage_rect;
 396
 397   LayerTreeHostImpl::FrameData frame;
 398   if (CommitAndComposite(frame_begin_time,
 399                          device_viewport_damage_rect,
 400                          false,  // for_readback
 401                          &frame)) {
 402     {
 403       DebugScopedSetMainThreadBlocked main_thread_blocked(this);
 404       DebugScopedSetImplThread impl(this);
 405
 406       // This CapturePostTasks should be destroyed before
 407       // DidCommitAndDrawFrame() is called since that goes out to the embedder,
 408       // and we want the embedder to receive its callbacks before that.
 409       // NOTE: This maintains consistent ordering with the ThreadProxy since
 410       // the DidCommitAndDrawFrame() must be post-tasked from the impl thread
 411       // there as the main thread is not blocked, so any posted tasks inside
 412       // the swap buffers will execute first.
 413       BlockingTaskRunner::CapturePostTasks blocked;
 414
 415       layer_tree_host_impl_->SwapBuffers(frame);
 416     }
 417     DidSwapFrame();
 418   }
 419 }
 420
 421 scoped_ptr<base::Value> SingleThreadProxy::AsValue() const {
 422   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
 423   {
 424     // The following line casts away const modifiers because it is just
 425     // setting debug state. We still want the AsValue() function and its
 426     // call chain to be const throughout.
 427     DebugScopedSetImplThread impl(const_cast<SingleThreadProxy*>(this));
 428
 429     state->Set("layer_tree_host_impl",
 430                layer_tree_host_impl_->AsValue().release());
 431   }
 432   return state.PassAs<base::Value>();
 433 }
 434
 435 void SingleThreadProxy::ForceSerializeOnSwapBuffers() {
 436   {
 437     DebugScopedSetImplThread impl(this);
 438     if (layer_tree_host_impl_->renderer()) {
 439       DCHECK(!layer_tree_host_->output_surface_lost());
 440       layer_tree_host_impl_->renderer()->DoNoOp();
 441     }
 442   }
 443 }
 444
 445 bool SingleThreadProxy::CommitAndComposite(
 446     base::TimeTicks frame_begin_time,
 447     const gfx::Rect& device_viewport_damage_rect,
 448     bool for_readback,
 449     LayerTreeHostImpl::FrameData* frame) {
 450   TRACE_EVENT0("cc", "SingleThreadProxy::CommitAndComposite");
 451   DCHECK(Proxy::IsMainThread());
 452
 453   if (!layer_tree_host_->InitializeOutputSurfaceIfNeeded())
 454     return false;
 455
 456   layer_tree_host_->AnimateLayers(frame_begin_time);
 457
 458   if (PrioritizedResourceManager* contents_texture_manager =
 459       layer_tree_host_->contents_texture_manager()) {
 460     contents_texture_manager->UnlinkAndClearEvictedBackings();
 461     contents_texture_manager->SetMaxMemoryLimitBytes(
 462         layer_tree_host_impl_->memory_allocation_limit_bytes());
 463     contents_texture_manager->SetExternalPriorityCutoff(
 464         layer_tree_host_impl_->memory_allocation_priority_cutoff());
 465   }
 466
 467   scoped_ptr<ResourceUpdateQueue> queue =
 468       make_scoped_ptr(new ResourceUpdateQueue);
 469   layer_tree_host_->UpdateLayers(queue.get());
 470
 471   layer_tree_host_->WillCommit();
 472
 473   scoped_refptr<ContextProvider> offscreen_context_provider;
 474   if (renderer_capabilities_for_main_thread_.using_offscreen_context3d &&
 475       layer_tree_host_->needs_offscreen_context()) {
 476     offscreen_context_provider =
 477         layer_tree_host_->client()->OffscreenContextProvider();
 478     if (offscreen_context_provider.get() &&
 479         !offscreen_context_provider->BindToCurrentThread())
 480       offscreen_context_provider = NULL;
 481
 482     if (offscreen_context_provider.get())
 483       created_offscreen_context_provider_ = true;
 484   }
 485
 486   DoCommit(queue.Pass());
 487   bool result = DoComposite(offscreen_context_provider,
 488                             frame_begin_time,
 489                             device_viewport_damage_rect,
 490                             for_readback,
 491                             frame);
 492   layer_tree_host_->DidBeginMainFrame();
 493   return result;
 494 }
 495
 496 bool SingleThreadProxy::ShouldComposite() const {
 497   DCHECK(Proxy::IsImplThread());
 498   return layer_tree_host_impl_->visible() &&
 499          layer_tree_host_impl_->CanDraw();
 500 }
 501
 502 void SingleThreadProxy::UpdateBackgroundAnimateTicking() {
 503   DCHECK(Proxy::IsImplThread());
 504   layer_tree_host_impl_->UpdateBackgroundAnimateTicking(
 505       !ShouldComposite() && layer_tree_host_impl_->active_tree()->root_layer());
 506 }
 507
 508 bool SingleThreadProxy::DoComposite(
 509     scoped_refptr<ContextProvider> offscreen_context_provider,
 510     base::TimeTicks frame_begin_time,
 511     const gfx::Rect& device_viewport_damage_rect,
 512     bool for_readback,
 513     LayerTreeHostImpl::FrameData* frame) {
 514   TRACE_EVENT0("cc", "SingleThreadProxy::DoComposite");
 515   DCHECK(!layer_tree_host_->output_surface_lost());
 516
 517   bool lost_output_surface = false;
 518   {
 519     DebugScopedSetImplThread impl(this);
 520     base::AutoReset<bool> mark_inside(&inside_draw_, true);
 521
 522     layer_tree_host_impl_->SetOffscreenContextProvider(
 523         offscreen_context_provider);
 524
 525     bool can_do_readback = layer_tree_host_impl_->renderer()->CanReadPixels();
 526
 527     // We guard PrepareToDraw() with CanDraw() because it always returns a valid
 528     // frame, so can only be used when such a frame is possible. Since
 529     // DrawLayers() depends on the result of PrepareToDraw(), it is guarded on
 530     // CanDraw() as well.
 531     if (!ShouldComposite() || (for_readback && !can_do_readback)) {
 532       UpdateBackgroundAnimateTicking();
 533       return false;
 534     }
 535
 536     layer_tree_host_impl_->Animate(
 537         layer_tree_host_impl_->CurrentFrameTimeTicks(),
 538         layer_tree_host_impl_->CurrentFrameTime());
 539     UpdateBackgroundAnimateTicking();
 540
 541     if (!layer_tree_host_impl_->IsContextLost()) {
 542       layer_tree_host_impl_->PrepareToDraw(frame, device_viewport_damage_rect);
 543       layer_tree_host_impl_->DrawLayers(frame, frame_begin_time);
 544       layer_tree_host_impl_->DidDrawAllLayers(*frame);
 545     }
 546     lost_output_surface = layer_tree_host_impl_->IsContextLost();
 547
 548     bool start_ready_animations = true;
 549     layer_tree_host_impl_->UpdateAnimationState(start_ready_animations);
 550
 551     layer_tree_host_impl_->ResetCurrentFrameTimeForNextFrame();
 552   }
 553
 554   if (lost_output_surface) {
 555     ContextProvider* offscreen_contexts =
 556         layer_tree_host_impl_->offscreen_context_provider();
 557     if (offscreen_contexts)
 558       offscreen_contexts->VerifyContexts();
 559     layer_tree_host_->DidLoseOutputSurface();
 560     return false;
 561   }
 562
 563   return true;
 564 }
 565
 566 void SingleThreadProxy::DidSwapFrame() {
 567   if (next_frame_is_newly_committed_frame_) {
 568     next_frame_is_newly_committed_frame_ = false;
 569     layer_tree_host_->DidCommitAndDrawFrame();
 570   }
 571 }
 572
 573 bool SingleThreadProxy::CommitPendingForTesting() { return false; }
 574
 575 }  // namespace cc