cc: Rename VSync to BeginFrame

cc/scheduler/scheduler.h

Index: cc/scheduler/scheduler.h
diff --git a/cc/scheduler/scheduler.h b/cc/scheduler/scheduler.h
index fb1105b959586bf701a756e687d3b7ad1d0a787b..8690bb8900aad68097a847393d75a00e8c66c41e 100644
--- a/cc/scheduler/scheduler.h
+++ b/cc/scheduler/scheduler.h
@@ -31,7 +31,7 @@ struct ScheduledActionDrawAndSwapResult {
 
 class SchedulerClient {
  public:
-  virtual void ScheduledActionBeginFrame() = 0;
+  virtual void ScheduledActionBeginMainFrame() = 0;
   virtual ScheduledActionDrawAndSwapResult
   ScheduledActionDrawAndSwapIfPossible() = 0;
   virtual ScheduledActionDrawAndSwapResult
@@ -81,8 +81,8 @@ class CC_EXPORT Scheduler : FrameRateControllerClient {
 
   void DidSwapUseIncompleteTile();
 
-  void BeginFrameComplete();
-  void BeginFrameAborted();
+  void BeginMainFrameComplete();
+  void BeginMainFrameAborted();
 
   void SetMaxFramesPending(int max);
   int MaxFramesPending() const;
@@ -107,10 +107,10 @@ class CC_EXPORT Scheduler : FrameRateControllerClient {
 
   base::TimeTicks AnticipatedDrawTime();
 
-  base::TimeTicks LastVSyncTime();
+  base::TimeTicks LastBeginImplFrameTime();
 
   // FrameRateControllerClient implementation
-  virtual void VSyncTick(bool throttled) OVERRIDE;
+  virtual void BeginImplFrame(bool throttled) OVERRIDE;
 
  private:
   Scheduler(SchedulerClient* client,