Include timestamp with vsync-delineating input events

Source/Platform/chromium/public/WebInputHandlerClient.h

 /* Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
@@ skipping 66 matching lines @@
                                          double startTime,
                                          double duration) = 0;
 
     // Request another callback to WebInputHandler::animate().
     virtual void scheduleAnimation() = 0;
 
     // Returns whether there are any touch event handlers registered on the
     // given WebPoint.
     virtual bool haveTouchEventHandlersAt(WebPoint) = 0;
 
-    // Indicate that the final input event for the current vsync interval was received.
-    virtual void didReceiveLastInputEventForVSync() { }
+    // Indicate that the final input event for the current vsync interval was
+    // received. The frame time is given in the same time base as
+    // monotonicallyIncreasingTime().
+    virtual void didReceiveLastInputEventForVSync(double frameTimeSeconds) { }
 
 protected:
     virtual ~WebInputHandlerClient() { }
 };
 
 }
 
 #endif