Improve handling of dictionary conversions.

Source/modules/mediastream/MediaStreamEvent.cpp

 /*
  * Copyright (C) 2011 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.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 59 matching lines @@
 
 MediaStreamEvent::~MediaStreamEvent()
 {
 }
 
 MediaStream* MediaStreamEvent::stream() const
 {
     return m_stream.get();
 }
 
+MediaStream* MediaStreamEvent::stream(bool& isNull) const
+{
+    isNull = !m_stream;
+    return m_stream.get();
+}
+
 const AtomicString& MediaStreamEvent::interfaceName() const
 {
     return EventNames::MediaStreamEvent;
 }
 
 } // namespace WebCore