Add a UseCounter for HTMLMediaElement.controller

Source/core/html/HTMLMediaElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple 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
@@ skipping 3823 matching lines @@
     setControllerInternal(controller);
 }
 
 void HTMLMediaElement::setControllerInternal(PassRefPtr<MediaController> controller)
 {
     if (m_mediaController)
         m_mediaController->removeMediaElement(this);
 
     m_mediaController = controller;
 
-    if (m_mediaController)
+    if (m_mediaController) {
+        UseCounter::count(document(), UseCounter::HTMLMediaElementControllerNotNull);
         m_mediaController->addMediaElement(this);
+    }
 
     if (hasMediaControls())
         mediaControls()->setMediaController(m_mediaController ? m_mediaController.get() : static_cast<MediaControllerInterface*>(this));
 }
 
 void HTMLMediaElement::updateMediaController()
 {
     if (m_mediaController)
         m_mediaController->reportControllerState();
 }
@@ skipping 106 matching lines @@
 {
     m_mediaSource->setWebMediaSourceAndOpen(adoptPtr(webMediaSource));
 }
 
 bool HTMLMediaElement::isInteractiveContent() const
 {
     return fastHasAttribute(controlsAttr);
 }
 
 }