compositor-worker: Initialize CW machinery plumbing to compositor and fire CW rAF callbacks.

cc/trees/single_thread_proxy.h

 // 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.
 
 #ifndef CC_TREES_SINGLE_THREAD_PROXY_H_
 #define CC_TREES_SINGLE_THREAD_PROXY_H_
 
 #include <limits>
 
 #include "base/cancelable_callback.h"
@@ skipping 38 matching lines @@
   void SetNeedsRedraw(const gfx::Rect& damage_rect) override;
   void SetNextCommitWaitsForActivation() override;
   void NotifyInputThrottledUntilCommit() override {}
   void SetDeferCommits(bool defer_commits) override;
   bool CommitRequested() const override;
   bool BeginMainFrameRequested() const override;
   void MainThreadHasStoppedFlinging() override {}
   void Start(
       std::unique_ptr<BeginFrameSource> external_begin_frame_source) override;
   void Stop() override;
+  void SetMutator(std::unique_ptr<LayerTreeMutator> mutator) override;
   bool SupportsImplScrolling() const override;
   bool MainFrameWillHappenForTesting() override;
   void UpdateTopControlsState(TopControlsState constraints,
                               TopControlsState current,
                               bool animate) override;
 
   // SchedulerClient implementation
   void WillBeginImplFrame(const BeginFrameArgs& args) override;
   void DidFinishImplFrame() override;
   void ScheduledActionSendBeginMainFrame(const BeginFrameArgs& args) override;
@@ skipping 172 matching lines @@
  private:
   DebugScopedSetImplThread impl_thread_;
   DebugScopedSetMainThreadBlocked main_thread_blocked_;
 
   DISALLOW_COPY_AND_ASSIGN(DebugScopedSetImplThreadAndMainThreadBlocked);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_SINGLE_THREAD_PROXY_H_