Keep auxilliary media objects on the heap always.

Source/modules/mediasource/SourceBuffer.cpp

 /*
  * 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 141 matching lines @@
         appendMode = WebSourceBuffer::AppendModeSequence;
     if (!m_webSourceBuffer->setMode(appendMode)) {
         exceptionState.throwDOMException(InvalidStateError, "The mode may not be set while the SourceBuffer's append state is 'PARSING_MEDIA_SEGMENT'.");
         return;
     }
 
     // 7. Update the attribute to new mode.
     m_mode = newMode;
 }
 
-PassRefPtrWillBeRawPtr<TimeRanges> SourceBuffer::buffered(ExceptionState& exceptionState) const
+TimeRanges* SourceBuffer::buffered(ExceptionState& exceptionState) const
 {
     // Section 3.1 buffered attribute steps.
     // 1. If this object has been removed from the sourceBuffers attribute of the parent media source then throw an
     //    InvalidStateError exception and abort these steps.
     if (isRemoved()) {
         exceptionState.throwDOMException(InvalidStateError, "This SourceBuffer has been removed from the parent media source.");
         return nullptr;
     }
 
     // 2. Return a new static normalized TimeRanges object for the media segments buffered.
@@ skipping 590 matching lines @@
 {
     visitor->trace(m_source);
     visitor->trace(m_stream);
     visitor->trace(m_trackDefaults);
     visitor->trace(m_asyncEventQueue);
     RefCountedGarbageCollectedEventTargetWithInlineData<SourceBuffer>::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace blink