Reland of cc: Remove frame queuing from the scheduler.

cc/trees/single_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/single_thread_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/memory/ptr_util.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 271 matching lines @@
   return commit_requested_;
 }
 
 void SingleThreadProxy::Stop() {
   TRACE_EVENT0("cc", "SingleThreadProxy::stop");
   DCHECK(task_runner_provider_->IsMainThread());
   {
     DebugScopedSetMainThreadBlocked main_thread_blocked(task_runner_provider_);
     DebugScopedSetImplThread impl(task_runner_provider_);
 
+    // Prevent the scheduler from performing actions while we're in an
+    // inconsistent state.
+    if (scheduler_on_impl_thread_)
+      scheduler_on_impl_thread_->Stop();
     // Take away the CompositorFrameSink before destroying things so it doesn't
     // try to call into its client mid-shutdown.
     layer_tree_host_impl_->ReleaseCompositorFrameSink();
-
-    BlockingTaskRunner::CapturePostTasks blocked(
-        task_runner_provider_->blocking_main_thread_task_runner());
     scheduler_on_impl_thread_ = nullptr;
     layer_tree_host_impl_ = nullptr;
   }
-  layer_tree_host_ = NULL;
+  layer_tree_host_ = nullptr;
 }
 
 void SingleThreadProxy::SetMutator(std::unique_ptr<LayerTreeMutator> mutator) {
   DCHECK(task_runner_provider_->IsMainThread());
   DebugScopedSetImplThread impl(task_runner_provider_);
   layer_tree_host_impl_->SetLayerTreeMutator(std::move(mutator));
 }
 
 void SingleThreadProxy::OnCanDrawStateChanged(bool can_draw) {
   TRACE_EVENT1("cc", "SingleThreadProxy::OnCanDrawStateChanged", "can_draw",
@@ skipping 429 matching lines @@
 void SingleThreadProxy::DidFinishImplFrame() {
   layer_tree_host_impl_->DidFinishImplFrame();
 #if DCHECK_IS_ON()
   DCHECK(inside_impl_frame_)
       << "DidFinishImplFrame called while not inside an impl frame!";
   inside_impl_frame_ = false;
 #endif
 }
 
 }  // namespace cc