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

cc/trees/remote_channel_impl.h

 // Copyright 2016 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_REMOTE_CHANNEL_IMPL_H_
 #define CC_TREES_REMOTE_CHANNEL_IMPL_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "cc/base/cc_export.h"
@@ skipping 140 matching lines @@
   void SetNeedsRedraw(const gfx::Rect& damage_rect) override;
   void SetNextCommitWaitsForActivation() override;
   void NotifyInputThrottledUntilCommit() override;
   void SetDeferCommits(bool defer_commits) override;
   void MainThreadHasStoppedFlinging() override;
   bool CommitRequested() const override;
   bool BeginMainFrameRequested() const 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;
   void SetAuthoritativeVSyncInterval(const base::TimeDelta& interval) override;
   void UpdateTopControlsState(TopControlsState constraints,
                               TopControlsState current,
                               bool animate) override;
   void SetOutputIsSecure(bool output_is_secure) override;
   bool MainFrameWillHappenForTesting() override;
 
   // Called on impl thread.
   // ChannelImpl implementation
@@ skipping 44 matching lines @@
   CompositorThreadOnly compositor_thread_vars_unsafe_;
 
   base::WeakPtr<ProxyImpl> proxy_impl_weak_ptr_;
 
   DISALLOW_COPY_AND_ASSIGN(RemoteChannelImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_REMOTE_CHANNEL_IMPL_H_