WIP - compositor worker mega patch.

cc/trees/proxy_main.h

Index: cc/trees/proxy_main.h
diff --git a/cc/trees/proxy_main.h b/cc/trees/proxy_main.h
index b7d5d1b193aa43fd55a2511a51976b62d54fac8b..cfd8afc60447bd14bbc239716db26ecdb072e806 100644
--- a/cc/trees/proxy_main.h
+++ b/cc/trees/proxy_main.h
@@ -21,6 +21,7 @@ class AnimationEvents;
 class BeginFrameSource;
 class ChannelMain;
 class LayerTreeHost;
+class LayerTreeMutator;
 
 // This class aggregates all interactions that the impl side of the compositor
 // needs to have with the main side.
@@ -101,6 +102,7 @@ class CC_EXPORT ProxyMain : public Proxy {
   void Start(scoped_ptr<BeginFrameSource> external_begin_frame_source) override;
   void Stop() override;
   bool SupportsImplScrolling() const override;
+  void SetMutator(LayerTreeMutator*) override;
   bool MainFrameWillHappenForTesting() override;
   void SetChildrenNeedBeginFrames(bool children_need_begin_frames) override;
   void SetAuthoritativeVSyncInterval(const base::TimeDelta& interval) override;