Setting HTMLMediaElement.controller does not properly remove the 'mediagroup' content attribute

Source/core/html/HTMLMediaElement.h

 /*
  * 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 261 matching lines @@
     AudioSourceProvider* audioSourceProvider();
 #endif
 
     enum InvalidURLAction { DoNothing, Complain };
     bool isSafeToLoadURL(const KURL&, InvalidURLAction);
 
     const String& mediaGroup() const;
     void setMediaGroup(const String&);
 
     MediaController* controller() const;
-    void setController(PassRefPtr<MediaController>);
+    void setController(PassRefPtr<MediaController>); // Resets the MediaGroup and sets the MediaController.
 
 protected:
     HTMLMediaElement(const QualifiedName&, Document&, bool);
     virtual ~HTMLMediaElement();
 
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
     virtual void finishParsingChildren() OVERRIDE;
     virtual bool isURLAttribute(const Attribute&) const OVERRIDE;
     virtual void attach(const AttachContext& = AttachContext()) OVERRIDE;
 
     virtual void didMoveToNewDocument(Document& oldDocument) OVERRIDE;
 
     enum DisplayMode { Unknown, None, Poster, PosterWaitingForVideo, Video };
     DisplayMode displayMode() const { return m_displayMode; }
     virtual void setDisplayMode(DisplayMode mode) { m_displayMode = mode; }
 
     virtual bool isMediaElement() const OVERRIDE { return true; }
 
+    void setControllerInternal(PassRefPtr<MediaController>);
+
     // Restrictions to change default behaviors.
     enum BehaviorRestrictionFlags {
         NoRestrictions = 0,
         RequireUserGestureForLoadRestriction = 1 << 0,
         RequireUserGestureForRateChangeRestriction = 1 << 1,
         RequireUserGestureForFullscreenRestriction = 1 << 2,
         RequirePageConsentToLoadMediaRestriction = 1 << 3,
     };
     typedef unsigned BehaviorRestrictions;
 
@@ skipping 285 matching lines @@
 inline bool isHTMLMediaElement(const Node& node)
 {
     return node.isElementNode() && toElement(node).isMediaElement();
 }
 
 DEFINE_NODE_TYPE_CASTS_WITH_FUNCTION(HTMLMediaElement);
 
 } //namespace
 
 #endif