Oilpan: handle MediaControls like the GCed object it is.

Source/core/html/shadow/MediaControlElementTypes.h

 /*
  * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * 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.
@@ skipping 74 matching lines @@
     // needed, also.
     void setDoesFit(bool);
 
     MediaControlElementType displayType() { return m_displayType; }
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     MediaControlElement(MediaControls&, MediaControlElementType, HTMLElement*);
 
-    MediaControls& mediaControls() const { return m_mediaControls; }
+    MediaControls& mediaControls() const
+    {
+        ASSERT(m_mediaControls);
+        return *m_mediaControls;
+    }
     HTMLMediaElement& mediaElement() const;
 
     void setDisplayType(MediaControlElementType);
 
 private:
     // Hide or show based on our fits / wanted state.  We want to show
     // if and only if we're wanted and we fit.
     void updateShownState();
 
-    MediaControls& m_mediaControls;
+    RawPtrWillBeMember<MediaControls> m_mediaControls;

[sof, 2015/08/07 05:13:23]

Notice that the removal of raw pointer effort doesn't encompass references.

     MediaControlElementType m_displayType;
     RawPtrWillBeMember<HTMLElement> m_element;
     bool m_isWanted : 1;
     bool m_doesFit : 1;
 };
 
 // ----------------------------
 
 class MediaControlDivElement : public HTMLDivElement, public MediaControlElement {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(MediaControlDivElement);
@@ skipping 33 matching lines @@
 protected:
     MediaControlTimeDisplayElement(MediaControls&, MediaControlElementType);
 
 private:
     double m_currentValue;
 };
 
 } // namespace blink
 
 #endif // MediaControlElementTypes_h