cc: Add main frame timing info to frame timing tracker.

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 73ed039e582363026274a82024477ab30b26ad71..77a15884015b0d2f20c6c771effc0dfe3e4e77ed 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -107,6 +107,7 @@ class LayerTreeHostImplClient {
                                                     base::TimeDelta delay) = 0;
   virtual void DidActivateSyncTree() = 0;
   virtual void DidPrepareTiles() = 0;
+  virtual base::TimeTicks GetNextBeginImplFrameTimeIfRequested() const = 0;
 
   // Called when page scale animation has completed on the impl thread.
   virtual void DidCompletePageScaleAnimationOnImplThread() = 0;
@@ -522,6 +523,9 @@ class CC_EXPORT LayerTreeHostImpl
     return frame_timing_tracker_.get();
   }
 
+  void SetBeginMainFrameTime(base::TimeTicks frame_time);
+  void RecordMainFrameTiming();
+
  protected:
   LayerTreeHostImpl(
       const LayerTreeSettings& settings,
@@ -732,6 +736,7 @@ class CC_EXPORT LayerTreeHostImpl
   bool is_likely_to_require_a_draw_;
 
   scoped_ptr<FrameTimingTracker> frame_timing_tracker_;
+  base::TimeTicks main_frame_time_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };