Split ThreadProxy methods to ProxyMain and ProxyImpl.

cc/trees/thread_proxy.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/thread_proxy.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/auto_reset.h"
@@ skipping 50 matching lines @@
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner,
     scoped_ptr<BeginFrameSource> external_begin_frame_source)
     : Proxy(main_task_runner, impl_task_runner),
       main_thread_only_vars_unsafe_(this, layer_tree_host->id()),
       main_thread_or_blocked_vars_unsafe_(layer_tree_host),
       compositor_thread_vars_unsafe_(
           this,
           layer_tree_host->id(),
           layer_tree_host->rendering_stats_instrumentation(),
-          external_begin_frame_source.Pass()) {
+          external_begin_frame_source.Pass()),
+      blocked_main_commit_state_vars_unsafe_(nullptr) {
   TRACE_EVENT0("cc", "ThreadProxy::ThreadProxy");
   DCHECK(IsMainThread());
   DCHECK(this->layer_tree_host());
   // TODO(khushalsagar): Move this to LayerTreeHost#InitializeThreaded once
   // ThreadProxy is split. LayerTreeHost creates the channel and passes it to
   // ProxyMain#SetChannel.
   SetChannel(ThreadedChannel::Create(this, main_task_runner, impl_task_runner));
 }
 
 ThreadProxy::MainThreadOnly::MainThreadOnly(ThreadProxy* proxy,
                                             int layer_tree_host_id)
     : layer_tree_host_id(layer_tree_host_id),
       max_requested_pipeline_stage(NO_PIPELINE_STAGE),
       current_pipeline_stage(NO_PIPELINE_STAGE),
       final_pipeline_stage(NO_PIPELINE_STAGE),
       started(false),
       prepare_tiles_pending(false),
       defer_commits(false),
+      commit_waits_for_activation(false),
       weak_factory(proxy) {}
 
 ThreadProxy::MainThreadOnly::~MainThreadOnly() {}
 
 ThreadProxy::MainThreadOrBlockedMainThread::MainThreadOrBlockedMainThread(
     LayerTreeHost* host)
-    : layer_tree_host(host),
-      commit_waits_for_activation(false),
-      main_thread_inside_commit(false) {}
+    : layer_tree_host(host) {}
 
 ThreadProxy::MainThreadOrBlockedMainThread::~MainThreadOrBlockedMainThread() {}
 
 ThreadProxy::CompositorThreadOnly::CompositorThreadOnly(
     ThreadProxy* proxy,
     int layer_tree_host_id,
     RenderingStatsInstrumentation* rendering_stats_instrumentation,
     scoped_ptr<BeginFrameSource> external_begin_frame_source)
     : layer_tree_host_id(layer_tree_host_id),
-      commit_completion_event(NULL),
-      completion_event_for_commit_held_on_tree_activation(NULL),
+      commit_completion_event(nullptr),
+      completion_event_for_commit_held_on_tree_activation(nullptr),
       next_frame_is_newly_committed_frame(false),
       inside_draw(false),
       input_throttled_until_commit(false),
       smoothness_priority_expiration_notifier(
           proxy->ImplThreadTaskRunner(),
           base::Bind(&ThreadProxy::RenewTreePriority, base::Unretained(proxy)),
           base::TimeDelta::FromMilliseconds(
               kSmoothnessTakesPriorityExpirationDelay * 1000)),
       external_begin_frame_source(external_begin_frame_source.Pass()),
       rendering_stats_instrumentation(rendering_stats_instrumentation),
-      weak_factory(proxy) {
-}
+      weak_factory(proxy) {}
 
 ThreadProxy::CompositorThreadOnly::~CompositorThreadOnly() {}
 
 ThreadProxy::~ThreadProxy() {
   TRACE_EVENT0("cc", "ThreadProxy::~ThreadProxy");
   DCHECK(IsMainThread());
   DCHECK(!main().started);
 }
 
 void ThreadProxy::SetChannel(scoped_ptr<ThreadedChannel> threaded_channel) {
   threaded_channel_ = threaded_channel.Pass();
   main().channel_main = threaded_channel_.get();
 }
 
 void ThreadProxy::FinishAllRendering() {
   DCHECK(Proxy::IsMainThread());
   DCHECK(!main().defer_commits);
 
   // Make sure all GL drawing is finished on the impl thread.
   DebugScopedSetMainThreadBlocked main_thread_blocked(this);
   CompletionEvent completion;
-  Proxy::ImplThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::FinishAllRenderingOnImplThread,
-                 impl_thread_weak_ptr_,
-                 &completion));
+  main().channel_main->FinishAllRenderingOnImpl(&completion);
   completion.Wait();
 }
 
 bool ThreadProxy::IsStarted() const {
   DCHECK(Proxy::IsMainThread());
   return main().started;
 }
 
 bool ThreadProxy::CommitToActiveTree() const {
   // With ThreadProxy, we use a pending tree and activate it once it's ready to
   // draw to allow input to modify the active tree and draw during raster.
   return false;
 }
 
 void ThreadProxy::SetVisible(bool visible) {
   TRACE_EVENT1("cc", "ThreadProxy::SetVisible", "visible", visible);
   DebugScopedSetMainThreadBlocked main_thread_blocked(this);
 
   CompletionEvent completion;
-  Proxy::ImplThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::SetVisibleOnImplThread,
-                 impl_thread_weak_ptr_,
-                 &completion,
-                 visible));
+  main().channel_main->SetVisibleOnImpl(&completion, visible);
   completion.Wait();
 }
 
-void ThreadProxy::SetVisibleOnImplThread(CompletionEvent* completion,
-                                         bool visible) {
+void ThreadProxy::SetVisibleOnImpl(CompletionEvent* completion, bool visible) {
   TRACE_EVENT1("cc", "ThreadProxy::SetVisibleOnImplThread", "visible", visible);
   impl().layer_tree_host_impl->SetVisible(visible);
   impl().scheduler->SetVisible(visible);
   completion->Signal();
 }
 
 void ThreadProxy::SetThrottleFrameProduction(bool throttle) {
   TRACE_EVENT1("cc", "ThreadProxy::SetThrottleFrameProduction", "throttle",
                throttle);
   main().channel_main->SetThrottleFrameProductionOnImpl(throttle);
@@ skipping 10 matching lines @@
   DCHECK(IsMainThread());
   layer_tree_host()->DidLoseOutputSurface();
 }
 
 void ThreadProxy::RequestNewOutputSurface() {
   DCHECK(IsMainThread());
   layer_tree_host()->RequestNewOutputSurface();
 }
 
 void ThreadProxy::SetOutputSurface(OutputSurface* output_surface) {
-  Proxy::ImplThreadTaskRunner()->PostTask(
-      FROM_HERE, base::Bind(&ThreadProxy::InitializeOutputSurfaceOnImplThread,
-                            impl_thread_weak_ptr_, output_surface));
+  main().channel_main->InitializeOutputSurfaceOnImpl(output_surface);
 }
 
 void ThreadProxy::ReleaseOutputSurface() {
   DCHECK(IsMainThread());
   DCHECK(layer_tree_host()->output_surface_lost());
 
   DebugScopedSetMainThreadBlocked main_thread_blocked(this);
   CompletionEvent completion;
-  Proxy::ImplThreadTaskRunner()->PostTask(
-      FROM_HERE, base::Bind(&ThreadProxy::ReleaseOutputSurfaceOnImplThread,
-                            impl_thread_weak_ptr_, &completion));
+  main().channel_main->ReleaseOutputSurfaceOnImpl(&completion);
   completion.Wait();
 }
 
 void ThreadProxy::DidInitializeOutputSurface(
     bool success,
     const RendererCapabilities& capabilities) {
   TRACE_EVENT0("cc", "ThreadProxy::DidInitializeOutputSurface");
   DCHECK(IsMainThread());
 
   if (!success) {
     layer_tree_host()->DidFailToInitializeOutputSurface();
     return;
   }
   main().renderer_capabilities_main_thread_copy = capabilities;
   layer_tree_host()->DidInitializeOutputSurface();
 }
 
-void ThreadProxy::SetRendererCapabilitiesMainThreadCopy(
+void ThreadProxy::SetRendererCapabilitiesMainCopy(
     const RendererCapabilities& capabilities) {
   main().renderer_capabilities_main_thread_copy = capabilities;
 }
 
 bool ThreadProxy::SendCommitRequestToImplThreadIfNeeded(
     CommitPipelineStage required_stage) {
   DCHECK(IsMainThread());
   DCHECK_NE(NO_PIPELINE_STAGE, required_stage);
   bool already_posted =
       main().max_requested_pipeline_stage != NO_PIPELINE_STAGE;
   main().max_requested_pipeline_stage =
       std::max(main().max_requested_pipeline_stage, required_stage);
   if (already_posted)
     return false;
-  Proxy::ImplThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::SetNeedsCommitOnImplThread,
-                 impl_thread_weak_ptr_));
+  main().channel_main->SetNeedsCommitOnImpl();
   return true;
 }
 
+void ThreadProxy::SetNeedsCommitOnImpl() {
+  SetNeedsCommitOnImplThread();
+}
+
 void ThreadProxy::DidCompletePageScaleAnimation() {
   DCHECK(IsMainThread());
   layer_tree_host()->DidCompletePageScaleAnimation();
 }
 
 const RendererCapabilities& ThreadProxy::GetRendererCapabilities() const {
   DCHECK(IsMainThread());
   DCHECK(!layer_tree_host()->output_surface_lost());
   return main().renderer_capabilities_main_thread_copy;
 }
@@ skipping 31 matching lines @@
     return;
   }
   if (SendCommitRequestToImplThreadIfNeeded(COMMIT_PIPELINE_STAGE)) {
     TRACE_EVENT_INSTANT0("cc", "ThreadProxy::SetNeedsCommit",
                          TRACE_EVENT_SCOPE_THREAD);
   }
 }
 
 void ThreadProxy::UpdateRendererCapabilitiesOnImplThread() {
   DCHECK(IsImplThread());
-  Proxy::MainThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::SetRendererCapabilitiesMainThreadCopy,
-                 main_thread_weak_ptr_,
-                 impl()
-                     .layer_tree_host_impl->GetRendererCapabilities()
-                     .MainThreadCapabilities()));
+  impl().channel_impl->SetRendererCapabilitiesMainCopy(
+      impl()
+          .layer_tree_host_impl->GetRendererCapabilities()
+          .MainThreadCapabilities());
 }
 
 void ThreadProxy::DidLoseOutputSurfaceOnImplThread() {
   TRACE_EVENT0("cc", "ThreadProxy::DidLoseOutputSurfaceOnImplThread");
   DCHECK(IsImplThread());
-  Proxy::MainThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::DidLoseOutputSurface, main_thread_weak_ptr_));
+  impl().channel_impl->DidLoseOutputSurface();
   impl().scheduler->DidLoseOutputSurface();
 }
 
 void ThreadProxy::CommitVSyncParameters(base::TimeTicks timebase,
                                         base::TimeDelta interval) {
   impl().scheduler->CommitVSyncParameters(timebase, interval);
 }
 
 void ThreadProxy::SetEstimatedParentDrawTime(base::TimeDelta draw_time) {
   impl().scheduler->SetEstimatedParentDrawTime(draw_time);
@@ skipping 59 matching lines @@
   // In tests the layer tree is destroyed after the scheduler is.
   if (impl().scheduler)
     impl().scheduler->SetVideoNeedsBeginFrames(needs_begin_frames);
 }
 
 void ThreadProxy::PostAnimationEventsToMainThreadOnImplThread(
     scoped_ptr<AnimationEventsVector> events) {
   TRACE_EVENT0("cc",
                "ThreadProxy::PostAnimationEventsToMainThreadOnImplThread");
   DCHECK(IsImplThread());
-  Proxy::MainThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::SetAnimationEvents,
-                 main_thread_weak_ptr_,
-                 base::Passed(&events)));
+  impl().channel_impl->SetAnimationEvents(events.Pass());
 }
 
 bool ThreadProxy::IsInsideDraw() { return impl().inside_draw; }
 
 void ThreadProxy::SetNeedsRedraw(const gfx::Rect& damage_rect) {
   TRACE_EVENT0("cc", "ThreadProxy::SetNeedsRedraw");
   DCHECK(IsMainThread());
-  Proxy::ImplThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::SetNeedsRedrawRectOnImplThread,
-                 impl_thread_weak_ptr_,
-                 damage_rect));
+  main().channel_main->SetNeedsRedrawOnImpl(damage_rect);
+}
+
+void ThreadProxy::SetNeedsRedrawOnImpl(const gfx::Rect& damage_rect) {
+  DCHECK(IsImplThread());
+  SetNeedsRedrawRectOnImplThread(damage_rect);
 }
 
 void ThreadProxy::SetNextCommitWaitsForActivation() {
   DCHECK(IsMainThread());
-  DCHECK(!blocked_main().main_thread_inside_commit);
-  blocked_main().commit_waits_for_activation = true;
+  main().commit_waits_for_activation = true;
 }
 
 void ThreadProxy::SetDeferCommits(bool defer_commits) {
   DCHECK(IsMainThread());
   if (main().defer_commits == defer_commits)
     return;
 
   main().defer_commits = defer_commits;
   if (main().defer_commits)
     TRACE_EVENT_ASYNC_BEGIN0("cc", "ThreadProxy::SetDeferCommits", this);
   else
     TRACE_EVENT_ASYNC_END0("cc", "ThreadProxy::SetDeferCommits", this);
 
-  Proxy::ImplThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::SetDeferCommitsOnImplThread,
-                 impl_thread_weak_ptr_,
-                 defer_commits));
+  main().channel_main->SetDeferCommitsOnImpl(defer_commits);
 }
 
-void ThreadProxy::SetDeferCommitsOnImplThread(bool defer_commits) const {
+void ThreadProxy::SetDeferCommitsOnImpl(bool defer_commits) {
   DCHECK(IsImplThread());
   impl().scheduler->SetDeferCommits(defer_commits);
 }
 
 bool ThreadProxy::CommitRequested() const {
   DCHECK(IsMainThread());
   // TODO(skyostil): Split this into something like CommitRequested() and
   // CommitInProgress().
   return main().current_pipeline_stage != NO_PIPELINE_STAGE ||
          main().max_requested_pipeline_stage >= COMMIT_PIPELINE_STAGE;
@@ skipping 22 matching lines @@
 }
 
 void ThreadProxy::SetNeedsRedrawRectOnImplThread(const gfx::Rect& damage_rect) {
   DCHECK(IsImplThread());
   impl().layer_tree_host_impl->SetViewportDamage(damage_rect);
   SetNeedsRedrawOnImplThread();
 }
 
 void ThreadProxy::MainThreadHasStoppedFlinging() {
   DCHECK(IsMainThread());
-  Proxy::ImplThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::MainThreadHasStoppedFlingingOnImplThread,
-                 impl_thread_weak_ptr_));
+  main().channel_main->MainThreadHasStoppedFlingingOnImpl();
 }
 
-void ThreadProxy::MainThreadHasStoppedFlingingOnImplThread() {
+void ThreadProxy::MainThreadHasStoppedFlingingOnImpl() {
   DCHECK(IsImplThread());
   impl().layer_tree_host_impl->MainThreadHasStoppedFlinging();
 }
 
 void ThreadProxy::NotifyInputThrottledUntilCommit() {
   DCHECK(IsMainThread());
-  Proxy::ImplThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::SetInputThrottledUntilCommitOnImplThread,
-                 impl_thread_weak_ptr_,
-                 true));
+  main().channel_main->SetInputThrottledUntilCommitOnImpl(true);
 }
 
-void ThreadProxy::SetInputThrottledUntilCommitOnImplThread(bool is_throttled) {
+void ThreadProxy::SetInputThrottledUntilCommitOnImpl(bool is_throttled) {
   DCHECK(IsImplThread());
   if (is_throttled == impl().input_throttled_until_commit)
     return;
   impl().input_throttled_until_commit = is_throttled;
   RenewTreePriority();
 }
 
 LayerTreeHost* ThreadProxy::layer_tree_host() {
   return blocked_main().layer_tree_host;
 }
@@ skipping 15 matching lines @@
   DCHECK(IsMainThread() || IsMainThreadBlocked());
   return main_thread_or_blocked_vars_unsafe_;
 }
 
 const ThreadProxy::MainThreadOrBlockedMainThread& ThreadProxy::blocked_main()
     const {
   DCHECK(IsMainThread() || IsMainThreadBlocked());
   return main_thread_or_blocked_vars_unsafe_;
 }
 
+const BlockedMainCommitState* ThreadProxy::blocked_commit_state() const {

[vmpstr, 2015/10/19 18:08:07]

Can this be moved into a separate patch? Let's just do the post task to channel
transition here. What do you think?

[Khushal, 2015/10/20 11:58:26]

Sounds good, will handle this in the next patch.

+  DCHECK(IsImplThread() && IsMainThreadBlocked() &&
+         impl().commit_completion_event);
+  return blocked_main_commit_state_vars_unsafe_;
+}
+
+void ThreadProxy::set_blocked_commit_state(
+    BlockedMainCommitState* blocked_main_commit_state) {
+  DCHECK(IsImplThread() && IsMainThreadBlocked() &&
+         impl().commit_completion_event);
+  blocked_main_commit_state_vars_unsafe_ = blocked_main_commit_state;
+}
+
 ThreadProxy::CompositorThreadOnly& ThreadProxy::impl() {
   DCHECK(IsImplThread());
   return compositor_thread_vars_unsafe_;
 }
 
 const ThreadProxy::CompositorThreadOnly& ThreadProxy::impl() const {
   DCHECK(IsImplThread());
   return compositor_thread_vars_unsafe_;
 }
 
@@ skipping 20 matching lines @@
   TRACE_EVENT0("cc", "ThreadProxy::Stop");
   DCHECK(IsMainThread());
   DCHECK(main().started);
 
   // Synchronously finishes pending GL operations and deletes the impl.
   // The two steps are done as separate post tasks, so that tasks posted
   // by the GL implementation due to the Finish can be executed by the
   // renderer before shutting it down.
   {
     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
-
     CompletionEvent completion;
-    Proxy::ImplThreadTaskRunner()->PostTask(
-        FROM_HERE,
-        base::Bind(&ThreadProxy::FinishGLOnImplThread,
-                   impl_thread_weak_ptr_,
-                   &completion));
+    main().channel_main->FinishGLOnImpl(&completion);
     completion.Wait();
   }
   {
     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
 
     CompletionEvent completion;
     Proxy::ImplThreadTaskRunner()->PostTask(
         FROM_HERE,
         base::Bind(&ThreadProxy::LayerTreeHostClosedOnImplThread,
                    impl_thread_weak_ptr_,
                    &completion));
     completion.Wait();
   }
 
   main().weak_factory.InvalidateWeakPtrs();
   blocked_main().layer_tree_host = NULL;
   main().started = false;
 }
 
 bool ThreadProxy::SupportsImplScrolling() const {
   return true;
 }
 
-void ThreadProxy::FinishAllRenderingOnImplThread(CompletionEvent* completion) {
+void ThreadProxy::FinishAllRenderingOnImpl(CompletionEvent* completion) {
   TRACE_EVENT0("cc", "ThreadProxy::FinishAllRenderingOnImplThread");
   DCHECK(IsImplThread());
   impl().layer_tree_host_impl->FinishAllRendering();
   completion->Signal();
 }
 
 void ThreadProxy::ScheduledActionSendBeginMainFrame() {
   unsigned int begin_frame_id = nextBeginFrameId++;
   benchmark_instrumentation::ScopedBeginFrameTask begin_frame_task(
       benchmark_instrumentation::kSendBeginFrame, begin_frame_id);
   scoped_ptr<BeginMainFrameAndCommitState> begin_main_frame_state(
       new BeginMainFrameAndCommitState);
   begin_main_frame_state->begin_frame_id = begin_frame_id;
   begin_main_frame_state->begin_frame_args =
       impl().layer_tree_host_impl->CurrentBeginFrameArgs();
   begin_main_frame_state->scroll_info =
       impl().layer_tree_host_impl->ProcessScrollDeltas();
   begin_main_frame_state->memory_allocation_limit_bytes =
       impl().layer_tree_host_impl->memory_allocation_limit_bytes();
   begin_main_frame_state->evicted_ui_resources =
       impl().layer_tree_host_impl->EvictedUIResourcesExist();
   // TODO(vmpstr): This needs to be fixed if
   // main_frame_before_activation_enabled is set, since we might run this code
   // twice before recording a duration. crbug.com/469824
   impl().last_begin_main_frame_args = begin_main_frame_state->begin_frame_args;
-  Proxy::MainThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::BeginMainFrame,
-                 main_thread_weak_ptr_,
-                 base::Passed(&begin_main_frame_state)));
+  impl().channel_impl->BeginMainFrame(begin_main_frame_state.Pass());
   devtools_instrumentation::DidRequestMainThreadFrame(
       impl().layer_tree_host_id);
 }
 
 void ThreadProxy::SendBeginMainFrameNotExpectedSoon() {
-  Proxy::MainThreadTaskRunner()->PostTask(
-      FROM_HERE, base::Bind(&ThreadProxy::BeginMainFrameNotExpectedSoon,
-                            main_thread_weak_ptr_));
+  impl().channel_impl->BeginMainFrameNotExpectedSoon();
 }
 
 void ThreadProxy::BeginMainFrame(
     scoped_ptr<BeginMainFrameAndCommitState> begin_main_frame_state) {
   benchmark_instrumentation::ScopedBeginFrameTask begin_frame_task(
       benchmark_instrumentation::kDoBeginFrame,
       begin_main_frame_state->begin_frame_id);
   TRACE_EVENT_SYNTHETIC_DELAY_BEGIN("cc.BeginMainFrame");
   DCHECK(IsMainThread());
   DCHECK_EQ(NO_PIPELINE_STAGE, main().current_pipeline_stage);
 
   if (main().defer_commits) {
     TRACE_EVENT_INSTANT0("cc", "EarlyOut_DeferCommit",
                          TRACE_EVENT_SCOPE_THREAD);
-    Proxy::ImplThreadTaskRunner()->PostTask(
-        FROM_HERE, base::Bind(&ThreadProxy::BeginMainFrameAbortedOnImplThread,
-                              impl_thread_weak_ptr_,
-                              CommitEarlyOutReason::ABORTED_DEFERRED_COMMIT));
+    main().channel_main->BeginMainFrameAbortedOnImpl(
+        CommitEarlyOutReason::ABORTED_DEFERRED_COMMIT);
     return;
   }
 
   // If the commit finishes, LayerTreeHost will transfer its swap promises to
   // LayerTreeImpl. The destructor of ScopedSwapPromiseChecker aborts the
   // remaining swap promises.
   ScopedAbortRemainingSwapPromises swap_promise_checker(layer_tree_host());
 
   main().final_pipeline_stage = main().max_requested_pipeline_stage;
   main().max_requested_pipeline_stage = NO_PIPELINE_STAGE;
 
   if (!layer_tree_host()->visible()) {
     TRACE_EVENT_INSTANT0("cc", "EarlyOut_NotVisible", TRACE_EVENT_SCOPE_THREAD);
-    Proxy::ImplThreadTaskRunner()->PostTask(
-        FROM_HERE, base::Bind(&ThreadProxy::BeginMainFrameAbortedOnImplThread,
-                              impl_thread_weak_ptr_,
-                              CommitEarlyOutReason::ABORTED_NOT_VISIBLE));
+    main().channel_main->BeginMainFrameAbortedOnImpl(
+        CommitEarlyOutReason::ABORTED_NOT_VISIBLE);
     return;
   }
 
   if (layer_tree_host()->output_surface_lost()) {
     TRACE_EVENT_INSTANT0(
         "cc", "EarlyOut_OutputSurfaceLost", TRACE_EVENT_SCOPE_THREAD);
-    Proxy::ImplThreadTaskRunner()->PostTask(
-        FROM_HERE,
-        base::Bind(&ThreadProxy::BeginMainFrameAbortedOnImplThread,
-                   impl_thread_weak_ptr_,
-                   CommitEarlyOutReason::ABORTED_OUTPUT_SURFACE_LOST));
+    main().channel_main->BeginMainFrameAbortedOnImpl(
+        CommitEarlyOutReason::ABORTED_OUTPUT_SURFACE_LOST);
     return;
   }
 
   main().current_pipeline_stage = ANIMATE_PIPELINE_STAGE;
 
   layer_tree_host()->ApplyScrollAndScale(
       begin_main_frame_state->scroll_info.get());
 
   layer_tree_host()->WillBeginMainFrame();
 
@@ skipping 18 matching lines @@
       main().final_pipeline_stage >= UPDATE_LAYERS_PIPELINE_STAGE;
   bool updated = should_update_layers && layer_tree_host()->UpdateLayers();
 
   layer_tree_host()->WillCommit();
   devtools_instrumentation::ScopedCommitTrace commit_task(
       layer_tree_host()->id());
 
   main().current_pipeline_stage = COMMIT_PIPELINE_STAGE;
   if (!updated && can_cancel_this_commit) {
     TRACE_EVENT_INSTANT0("cc", "EarlyOut_NoUpdates", TRACE_EVENT_SCOPE_THREAD);
-    Proxy::ImplThreadTaskRunner()->PostTask(
-        FROM_HERE, base::Bind(&ThreadProxy::BeginMainFrameAbortedOnImplThread,
-                              impl_thread_weak_ptr_,
-                              CommitEarlyOutReason::FINISHED_NO_UPDATES));
+    main().channel_main->BeginMainFrameAbortedOnImpl(
+        CommitEarlyOutReason::FINISHED_NO_UPDATES);
 
     // Although the commit is internally aborted, this is because it has been
     // detected to be a no-op.  From the perspective of an embedder, this commit
     // went through, and input should no longer be throttled, etc.
     main().current_pipeline_stage = NO_PIPELINE_STAGE;
     layer_tree_host()->CommitComplete();
     layer_tree_host()->DidBeginMainFrame();
     layer_tree_host()->BreakSwapPromises(SwapPromise::COMMIT_NO_UPDATE);
     return;
   }
 
   // Notify the impl thread that the main thread is ready to commit. This will
   // begin the commit process, which is blocking from the main thread's
   // point of view, but asynchronously performed on the impl thread,
   // coordinated by the Scheduler.
   {
     TRACE_EVENT0("cc", "ThreadProxy::BeginMainFrame::commit");
 
     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
 
     // This CapturePostTasks should be destroyed before CommitComplete() is
     // called since that goes out to the embedder, and we want the embedder
     // to receive its callbacks before that.
     BlockingTaskRunner::CapturePostTasks blocked(
         blocking_main_thread_task_runner());
 
     CompletionEvent completion;
-    Proxy::ImplThreadTaskRunner()->PostTask(
-        FROM_HERE, base::Bind(&ThreadProxy::StartCommitOnImplThread,
-                              impl_thread_weak_ptr_, &completion));
+    BlockedMainCommitState blocked_main_commit_state;
+    blocked_main_commit_state.layer_tree_host = layer_tree_host();
+    blocked_main_commit_state.commit_waits_for_activation =
+        &main().commit_waits_for_activation;
+    main().channel_main->StartCommitOnImpl(&completion,
+                                           &blocked_main_commit_state);
     completion.Wait();
   }
 
   main().current_pipeline_stage = NO_PIPELINE_STAGE;
   layer_tree_host()->CommitComplete();
   layer_tree_host()->DidBeginMainFrame();
 }
 
 void ThreadProxy::BeginMainFrameNotExpectedSoon() {
   TRACE_EVENT0("cc", "ThreadProxy::BeginMainFrameNotExpectedSoon");
   DCHECK(IsMainThread());
   layer_tree_host()->BeginMainFrameNotExpectedSoon();
 }
 
-void ThreadProxy::StartCommitOnImplThread(CompletionEvent* completion) {
+void ThreadProxy::StartCommitOnImpl(
+    CompletionEvent* completion,
+    BlockedMainCommitState* blocked_main_commit_state) {
   TRACE_EVENT0("cc", "ThreadProxy::StartCommitOnImplThread");
   DCHECK(!impl().commit_completion_event);
   DCHECK(IsImplThread() && IsMainThreadBlocked());
   DCHECK(impl().scheduler);
   DCHECK(impl().scheduler->CommitPending());
 
   if (!impl().layer_tree_host_impl) {
     TRACE_EVENT_INSTANT0(
         "cc", "EarlyOut_NoLayerTree", TRACE_EVENT_SCOPE_THREAD);
-    completion->Signal();

[vmpstr, 2015/10/19 18:08:07]

We can keep the completion logic as is for now and follow-up with one of the
approaches we discussed offline. 

[Khushal, 2015/10/20 11:58:26]

Sounds good. I've added the methods we discussed to CompletionEvent. I think
regularly checking the event for IsSignaled might be equivalent to blocking the
thread, which we'd want to avoid on the client. We can change it if it turns out
to be a problem.

     return;
   }
 
   // Ideally, we should inform to impl thread when BeginMainFrame is started.
   // But, we can avoid a PostTask in here.
   impl().scheduler->NotifyBeginMainFrameStarted();
   impl().commit_completion_event = completion;
+  DCHECK(!blocked_commit_state());
+  set_blocked_commit_state(blocked_main_commit_state);
   impl().scheduler->NotifyReadyToCommit();
 }
 
-void ThreadProxy::BeginMainFrameAbortedOnImplThread(
-    CommitEarlyOutReason reason) {
+void ThreadProxy::BeginMainFrameAbortedOnImpl(CommitEarlyOutReason reason) {
   TRACE_EVENT1("cc", "ThreadProxy::BeginMainFrameAbortedOnImplThread", "reason",
                CommitEarlyOutReasonToString(reason));
   DCHECK(IsImplThread());
   DCHECK(impl().scheduler);
   DCHECK(impl().scheduler->CommitPending());
   DCHECK(!impl().layer_tree_host_impl->pending_tree());
 
   if (CommitEarlyOutHandledCommit(reason)) {
-    SetInputThrottledUntilCommitOnImplThread(false);
+    SetInputThrottledUntilCommitOnImpl(false);
     impl().last_processed_begin_main_frame_args =
         impl().last_begin_main_frame_args;
   }
   impl().layer_tree_host_impl->BeginMainFrameAborted(reason);
   impl().scheduler->BeginMainFrameAborted(reason);
 }
 
 void ThreadProxy::ScheduledActionAnimate() {
   TRACE_EVENT0("cc", "ThreadProxy::ScheduledActionAnimate");
   DCHECK(IsImplThread());
 
   impl().layer_tree_host_impl->Animate();
 }
 
 void ThreadProxy::ScheduledActionCommit() {
   TRACE_EVENT0("cc", "ThreadProxy::ScheduledActionCommit");
   DCHECK(IsImplThread());
   DCHECK(IsMainThreadBlocked());
   DCHECK(impl().commit_completion_event);
+  DCHECK(blocked_commit_state());
 
-  blocked_main().main_thread_inside_commit = true;
   impl().layer_tree_host_impl->BeginCommit();
-  layer_tree_host()->FinishCommitOnImplThread(
+  blocked_commit_state()->layer_tree_host->FinishCommitOnImplThread(
       impl().layer_tree_host_impl.get());
-  blocked_main().main_thread_inside_commit = false;
 
-  bool hold_commit = blocked_main().commit_waits_for_activation;
-  blocked_main().commit_waits_for_activation = false;
+  bool hold_commit = *(blocked_commit_state()->commit_waits_for_activation);
+  *(blocked_commit_state()->commit_waits_for_activation) = false;
 
   if (hold_commit) {
     // For some layer types in impl-side painting, the commit is held until
     // the sync tree is activated.  It's also possible that the
     // sync tree has already activated if there was no work to be done.
     TRACE_EVENT_INSTANT0("cc", "HoldCommit", TRACE_EVENT_SCOPE_THREAD);
     impl().completion_event_for_commit_held_on_tree_activation =
         impl().commit_completion_event;
-    impl().commit_completion_event = NULL;
+    set_blocked_commit_state(nullptr);
+    impl().commit_completion_event = nullptr;
   } else {
+    set_blocked_commit_state(nullptr);
     impl().commit_completion_event->Signal();
-    impl().commit_completion_event = NULL;
+    impl().commit_completion_event = nullptr;
   }
 
   impl().scheduler->DidCommit();
 
   // Delay this step until afer the main thread has been released as it's
   // often a good bit of work to update the tree and prepare the new frame.
   impl().layer_tree_host_impl->CommitComplete();
 
-  SetInputThrottledUntilCommitOnImplThread(false);
+  SetInputThrottledUntilCommitOnImpl(false);
 
   impl().next_frame_is_newly_committed_frame = true;
 }
 
 void ThreadProxy::ScheduledActionActivateSyncTree() {
   TRACE_EVENT0("cc", "ThreadProxy::ScheduledActionActivateSyncTree");
   DCHECK(IsImplThread());
   impl().layer_tree_host_impl->ActivateSyncTree();
 }
 
 void ThreadProxy::ScheduledActionBeginOutputSurfaceCreation() {
   TRACE_EVENT0("cc", "ThreadProxy::ScheduledActionBeginOutputSurfaceCreation");
   DCHECK(IsImplThread());
-  Proxy::MainThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::RequestNewOutputSurface, main_thread_weak_ptr_));
+  impl().channel_impl->RequestNewOutputSurface();
 }
 
 DrawResult ThreadProxy::DrawSwapInternal(bool forced_draw) {
   TRACE_EVENT_SYNTHETIC_DELAY("cc.DrawAndSwap");
   DrawResult result;
 
   DCHECK(IsImplThread());
   DCHECK(impl().layer_tree_host_impl.get());
 
   base::AutoReset<bool> mark_inside(&impl().inside_draw, true);
@@ skipping 35 matching lines @@
 
   bool start_ready_animations = draw_frame;
   impl().layer_tree_host_impl->UpdateAnimationState(start_ready_animations);
 
   if (draw_frame)
     impl().layer_tree_host_impl->SwapBuffers(frame);
 
   // Tell the main thread that the the newly-commited frame was drawn.
   if (impl().next_frame_is_newly_committed_frame) {
     impl().next_frame_is_newly_committed_frame = false;
-    Proxy::MainThreadTaskRunner()->PostTask(
-        FROM_HERE,
-        base::Bind(&ThreadProxy::DidCommitAndDrawFrame, main_thread_weak_ptr_));
+    impl().channel_impl->DidCommitAndDrawFrame();
   }
 
   DCHECK_NE(INVALID_RESULT, result);
   return result;
 }
 
 void ThreadProxy::ScheduledActionPrepareTiles() {
   TRACE_EVENT0("cc", "ThreadProxy::ScheduledActionPrepareTiles");
   impl().layer_tree_host_impl->PrepareTiles();
 }
@@ skipping 73 matching lines @@
       this, scheduler_settings, impl().layer_tree_host_id,
       ImplThreadTaskRunner(), impl().external_begin_frame_source.get(),
       compositor_timing_history.Pass());
 
   DCHECK_EQ(impl().scheduler->visible(),
             impl().layer_tree_host_impl->visible());
   impl_thread_weak_ptr_ = impl().weak_factory.GetWeakPtr();
   completion->Signal();
 }
 
-void ThreadProxy::InitializeOutputSurfaceOnImplThread(
-    OutputSurface* output_surface) {
+void ThreadProxy::InitializeOutputSurfaceOnImpl(OutputSurface* output_surface) {
   TRACE_EVENT0("cc", "ThreadProxy::InitializeOutputSurfaceOnImplThread");
   DCHECK(IsImplThread());
 
   LayerTreeHostImpl* host_impl = impl().layer_tree_host_impl.get();
   bool success = host_impl->InitializeRenderer(output_surface);
   RendererCapabilities capabilities;
   if (success) {
     capabilities =
         host_impl->GetRendererCapabilities().MainThreadCapabilities();
   }
 
-  Proxy::MainThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::DidInitializeOutputSurface,
-                 main_thread_weak_ptr_,
-                 success,
-                 capabilities));
+  impl().channel_impl->DidInitializeOutputSurface(success, capabilities);
 
   if (success)
     impl().scheduler->DidCreateAndInitializeOutputSurface();
 }
 
-void ThreadProxy::ReleaseOutputSurfaceOnImplThread(
-    CompletionEvent* completion) {
+void ThreadProxy::ReleaseOutputSurfaceOnImpl(CompletionEvent* completion) {
   DCHECK(IsImplThread());
 
   // Unlike DidLoseOutputSurfaceOnImplThread, we don't need to call
   // LayerTreeHost::DidLoseOutputSurface since it already knows.
   impl().scheduler->DidLoseOutputSurface();
   impl().layer_tree_host_impl->ReleaseOutputSurface();
   completion->Signal();
 }
 
-void ThreadProxy::FinishGLOnImplThread(CompletionEvent* completion) {
+void ThreadProxy::FinishGLOnImpl(CompletionEvent* completion) {
   TRACE_EVENT0("cc", "ThreadProxy::FinishGLOnImplThread");
   DCHECK(IsImplThread());
   if (impl().layer_tree_host_impl->output_surface()) {
     ContextProvider* context_provider =
         impl().layer_tree_host_impl->output_surface()->context_provider();
     if (context_provider)
       context_provider->ContextGL()->Finish();
   }
   completion->Signal();
 }
 
 void ThreadProxy::LayerTreeHostClosedOnImplThread(CompletionEvent* completion) {
   TRACE_EVENT0("cc", "ThreadProxy::LayerTreeHostClosedOnImplThread");
   DCHECK(IsImplThread());
   DCHECK(IsMainThreadBlocked());
   impl().scheduler = nullptr;
   impl().external_begin_frame_source = nullptr;
   impl().layer_tree_host_impl = nullptr;
   impl().weak_factory.InvalidateWeakPtrs();
   // We need to explicitly shutdown the notifier to destroy any weakptrs it is
   // holding while still on the compositor thread. This also ensures any
   // callbacks holding a ThreadProxy pointer are cancelled.
   impl().smoothness_priority_expiration_notifier.Shutdown();
   completion->Signal();
 }
 
-ThreadProxy::BeginMainFrameAndCommitState::BeginMainFrameAndCommitState()
-    : memory_allocation_limit_bytes(0),
-      evicted_ui_resources(false) {}
-
-ThreadProxy::BeginMainFrameAndCommitState::~BeginMainFrameAndCommitState() {}
-
 bool ThreadProxy::MainFrameWillHappenForTesting() {
   DCHECK(IsMainThread());
-  CompletionEvent completion;
   bool main_frame_will_happen = false;
   {
     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
-    Proxy::ImplThreadTaskRunner()->PostTask(
-        FROM_HERE,
-        base::Bind(&ThreadProxy::MainFrameWillHappenOnImplThreadForTesting,
-                   impl_thread_weak_ptr_,
-                   &completion,
-                   &main_frame_will_happen));
+    CompletionEvent completion;
+    main().channel_main->MainFrameWillHappenOnImplForTesting(
+        &completion, &main_frame_will_happen);
     completion.Wait();
   }
   return main_frame_will_happen;
 }
 
 void ThreadProxy::SetChildrenNeedBeginFrames(bool children_need_begin_frames) {
   NOTREACHED() << "Only used by SingleThreadProxy";
 }
 
-void ThreadProxy::MainFrameWillHappenOnImplThreadForTesting(
+void ThreadProxy::MainFrameWillHappenOnImplForTesting(
     CompletionEvent* completion,
     bool* main_frame_will_happen) {
   DCHECK(IsImplThread());
   if (impl().layer_tree_host_impl->output_surface()) {
     *main_frame_will_happen = impl().scheduler->MainFrameForTestingWillHappen();
   } else {
     *main_frame_will_happen = false;
   }
   completion->Signal();
 }
@@ skipping 55 matching lines @@
 }
 
 void ThreadProxy::DidActivateSyncTree() {
   TRACE_EVENT0("cc", "ThreadProxy::DidActivateSyncTreeOnImplThread");
   DCHECK(IsImplThread());
 
   if (impl().completion_event_for_commit_held_on_tree_activation) {
     TRACE_EVENT_INSTANT0(
         "cc", "ReleaseCommitbyActivation", TRACE_EVENT_SCOPE_THREAD);
     impl().completion_event_for_commit_held_on_tree_activation->Signal();
-    impl().completion_event_for_commit_held_on_tree_activation = NULL;
+    impl().completion_event_for_commit_held_on_tree_activation = nullptr;
   }
 
   impl().last_processed_begin_main_frame_args =
       impl().last_begin_main_frame_args;
 }
 
 void ThreadProxy::WillPrepareTiles() {
   DCHECK(IsImplThread());
   impl().scheduler->WillPrepareTiles();
 }
 
 void ThreadProxy::DidPrepareTiles() {
   DCHECK(IsImplThread());
   impl().scheduler->DidPrepareTiles();
 }
 
 void ThreadProxy::DidCompletePageScaleAnimationOnImplThread() {
   DCHECK(IsImplThread());
-  Proxy::MainThreadTaskRunner()->PostTask(
-      FROM_HERE, base::Bind(&ThreadProxy::DidCompletePageScaleAnimation,
-                            main_thread_weak_ptr_));
+  impl().channel_impl->DidCompletePageScaleAnimation();
 }
 
 void ThreadProxy::OnDrawForOutputSurface() {
   DCHECK(IsImplThread());
   impl().scheduler->OnDrawForOutputSurface();
 }
 
 void ThreadProxy::UpdateTopControlsState(TopControlsState constraints,
                                          TopControlsState current,
                                          bool animate) {
   main().channel_main->UpdateTopControlsStateOnImpl(constraints, current,
                                                     animate);
 }
 
 void ThreadProxy::UpdateTopControlsStateOnImpl(TopControlsState constraints,
                                                TopControlsState current,
                                                bool animate) {
   DCHECK(IsImplThread());
   impl().layer_tree_host_impl->top_controls_manager()->UpdateTopControlsState(
       constraints, current, animate);
 }
 
 void ThreadProxy::PostFrameTimingEventsOnImplThread(
     scoped_ptr<FrameTimingTracker::CompositeTimingSet> composite_events,
     scoped_ptr<FrameTimingTracker::MainFrameTimingSet> main_frame_events) {
   DCHECK(IsImplThread());
-  Proxy::MainThreadTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&ThreadProxy::PostFrameTimingEvents, main_thread_weak_ptr_,
-                 base::Passed(composite_events.Pass()),
-                 base::Passed(main_frame_events.Pass())));
+  impl().channel_impl->PostFrameTimingEventsOnMain(composite_events.Pass(),
+                                                   main_frame_events.Pass());
 }
 
-void ThreadProxy::PostFrameTimingEvents(
+void ThreadProxy::PostFrameTimingEventsOnMain(
     scoped_ptr<FrameTimingTracker::CompositeTimingSet> composite_events,
     scoped_ptr<FrameTimingTracker::MainFrameTimingSet> main_frame_events) {
   DCHECK(IsMainThread());
   layer_tree_host()->RecordFrameTimingEvents(composite_events.Pass(),
                                              main_frame_events.Pass());
 }
 
 base::WeakPtr<ProxyMain> ThreadProxy::GetMainWeakPtr() {
   return main_thread_weak_ptr_;
 }
 
 base::WeakPtr<ProxyImpl> ThreadProxy::GetImplWeakPtr() {
   return impl_thread_weak_ptr_;
 }
 
 }  // namespace cc