Fix WebMediaStreamTrack::ExtraData::owner()

public/platform/WebMediaStreamTrack.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:
  * 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 25 matching lines @@
 namespace blink {
 class WebAudioSourceProvider;
 class WebMediaStream;
 class WebMediaStreamSource;
 class WebString;
 
 class WebMediaStreamTrack {
 public:
     class ExtraData {
     public:
+        ExtraData() : m_owner(0) { }
         virtual ~ExtraData() { }
+
         BLINK_EXPORT WebMediaStreamTrack owner();
 
 #if INSIDE_BLINK
         BLINK_EXPORT void setOwner(WebCore::MediaStreamComponent*);
 #endif
 
     private:
         WebCore::MediaStreamComponent* m_owner;
     };
 
@@ skipping 40 matching lines @@
     operator WebCore::MediaStreamComponent*() const;
 #endif
 
 private:
     WebPrivatePtr<WebCore::MediaStreamComponent> m_private;
 };
 
 } // namespace blink
 
 #endif // WebMediaStreamTrack_h