Remove the lifetime hack in ImageLoader where it keeps its assoc element alive

third_party/WebKit/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
@@ skipping 272 matching lines @@
   MediaControls* GetMediaControls() const;
 
   // Notifies the media element that the media controls became visible, so
   // that text track layout may be updated to avoid overlapping them.
   void MediaControlsDidBecomeVisible();
 
   void SourceWasRemoved(HTMLSourceElement*);
   void SourceWasAdded(HTMLSourceElement*);
 
   // ScriptWrappable functions.
-  bool HasPendingActivity() const final;
+  bool HasPendingActivity() const override;
 
   AudioSourceProviderClient* AudioSourceNode() { return audio_source_node_; }
   void SetAudioSourceNode(AudioSourceProviderClient*);
 
   AudioSourceProvider& GetAudioSourceProvider() {
     return audio_source_provider_;
   }
 
   enum InvalidURLAction { kDoNothing, kComplain };
   bool IsSafeToLoadURL(const KURL&, InvalidURLAction);
@@ skipping 436 matching lines @@
 
 inline bool IsHTMLMediaElement(const HTMLElement& element) {
   return isHTMLAudioElement(element) || isHTMLVideoElement(element);
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLMediaElement);
 
 }  // namespace blink
 
 #endif  // HTMLMediaElement_h