Keep auxilliary media objects on the heap always.

Source/modules/mediasource/MediaSource.h

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 61 matching lines @@
     void endOfStream(const AtomicString& error, ExceptionState&);
     void endOfStream(ExceptionState&);
     static bool isTypeSupported(const String& type);
 
     // HTMLMediaSource
     bool attachToElement(HTMLMediaElement*) override;
     void setWebMediaSourceAndOpen(PassOwnPtr<WebMediaSource>) override;
     void close() override;
     bool isClosed() const override;
     double duration() const override;
-    PassRefPtrWillBeRawPtr<TimeRanges> buffered() const override;
-    PassRefPtrWillBeRawPtr<TimeRanges> seekable() const override;
+    TimeRanges* buffered() const override;
+    TimeRanges* seekable() const override;
 #if !ENABLE(OILPAN)
     void refHTMLMediaSource() override { ref(); }
     void derefHTMLMediaSource() override { deref(); }
 #endif
 
     // EventTarget interface
     const AtomicString& interfaceName() const override;
     ExecutionContext* executionContext() const override;
 
     // ActiveDOMObject interface
@@ skipping 37 matching lines @@
 
     Member<SourceBufferList> m_sourceBuffers;
     Member<SourceBufferList> m_activeSourceBuffers;
 
     bool m_isAddedToRegistry;
 };
 
 } // namespace blink
 
 #endif // MediaSource_h