compositor-worker: blink->cc plumbing

cc/trees/layer_tree_host.h

Index: cc/trees/layer_tree_host.h
diff --git a/cc/trees/layer_tree_host.h b/cc/trees/layer_tree_host.h
index da5d186427135b3f7769c25e36dd0b68d6001d6b..d0a695348e95f6e453c2429f4f730ffe2261f3cf 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -61,6 +61,7 @@ class Layer;
 class LayerTreeHostImpl;
 class LayerTreeHostImplClient;
 class LayerTreeHostSingleThreadClient;
+class LayerTreeMutator;
 class PropertyTrees;
 class Region;
 class RenderingStatsInstrumentation;
@@ -330,6 +331,8 @@ class CC_EXPORT LayerTreeHost : public MutatorHostClient {
       scoped_ptr<FrameTimingTracker::CompositeTimingSet> composite_events,
       scoped_ptr<FrameTimingTracker::MainFrameTimingSet> main_frame_events);
 
+  void SetLayerTreeMutator(LayerTreeMutator* mutator);
+
   Layer* LayerById(int id) const;
   void RegisterLayer(Layer* layer);
   void UnregisterLayer(Layer* layer);