cc: Block commit on activate by setting a flag on LayerTreeHost.

cc/trees/thread_proxy.h

Index: cc/trees/thread_proxy.h
diff --git a/cc/trees/thread_proxy.h b/cc/trees/thread_proxy.h
index 2637aef935a2bef4604ec34ac3b75169f5811ab5..b8d2d1d6461f41747231f099873767d2740e7062 100644
--- a/cc/trees/thread_proxy.h
+++ b/cc/trees/thread_proxy.h
@@ -52,6 +52,7 @@ class ThreadProxy : public Proxy,
   virtual void SetNeedsUpdateLayers() OVERRIDE;
   virtual void SetNeedsCommit() OVERRIDE;
   virtual void SetNeedsRedraw(gfx::Rect damage_rect) OVERRIDE;
+  virtual void SetNextCommitWaitsForActivation() OVERRIDE;
   virtual void NotifyInputThrottledUntilCommit() OVERRIDE;
   virtual void SetDeferCommits(bool defer_commits) OVERRIDE;
   virtual bool CommitRequested() const OVERRIDE;
@@ -203,6 +204,10 @@ class ThreadProxy : public Proxy,
   // anything else.
   scoped_ptr<OutputSurface> first_output_surface_;
 
+  // Accessed on the main thread, or when main thread is blocked.
+  bool commit_waits_for_activation_;
+  bool inside_commit_;
+
   base::WeakPtrFactory<ThreadProxy> weak_factory_on_impl_thread_;
 
   base::WeakPtr<ThreadProxy> main_thread_weak_ptr_;