cc: Rename VSync to BeginFrame

cc/output/output_surface.h

Index: cc/output/output_surface.h
diff --git a/cc/output/output_surface.h b/cc/output/output_surface.h
index e8d6fe3b3e4b9a033f3c4662b39f58e4143f1b47..008dc80fc516a7e94754ef22cfe5a591d53406ed 100644
--- a/cc/output/output_surface.h
+++ b/cc/output/output_surface.h
@@ -96,10 +96,10 @@ class CC_EXPORT OutputSurface {
   // processing should be stopped, or lowered in priority.
   virtual void UpdateSmoothnessTakesPriority(bool prefer_smoothness) {}
 
-  // Requests a vsync notification from the output surface. The notification
-  // will be delivered by calling OutputSurfaceClient::DidVSync for all future
-  // vsync events until the callback is disabled.
-  virtual void EnableVSyncNotification(bool enable_vsync) {}
+  // Requests a BeginImplFrame notification from the output surface. The
+  // notification will be delivered by calling
+  // OutputSurfaceClient::BeginImplFrame until the callback is disabled.
+  virtual void SetNeedsBeginImplFrame(bool enable) {}
 
  protected:
   OutputSurfaceClient* client_;