Remove unused ExtraData support on exported mediastream objects.

public/platform/WebRTCVoidRequest.h

 /*
  * 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:
  *
  *     * 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 24 matching lines @@
 #include "WebNonCopyable.h"
 #include "WebPrivatePtr.h"
 #include "WebString.h"
 
 namespace blink {
 
 class RTCVoidRequest;
 
 class WebRTCVoidRequest {
 public:
-    class ExtraData {
-    public:
-        virtual ~ExtraData() { }
-    };
-
     WebRTCVoidRequest() { }
     WebRTCVoidRequest(const WebRTCVoidRequest& other) { assign(other); }
     ~WebRTCVoidRequest() { reset(); }
 
     WebRTCVoidRequest& operator=(const WebRTCVoidRequest& other)
     {
         assign(other);
         return *this;
     }
 
     BLINK_PLATFORM_EXPORT void assign(const WebRTCVoidRequest&);
 
     BLINK_PLATFORM_EXPORT void reset();
     bool isNull() const { return m_private.isNull(); }
 
     BLINK_PLATFORM_EXPORT void requestSucceeded() const;
     BLINK_PLATFORM_EXPORT void requestFailed(const WebString& error) const;
 
-    // Extra data associated with this object.
-    // If non-null, the extra data pointer will be deleted when the object is destroyed.
-    // Setting the extra data pointer will cause any existing non-null
-    // extra data pointer to be deleted.
-    BLINK_PLATFORM_EXPORT ExtraData* extraData() const;
-    BLINK_PLATFORM_EXPORT void setExtraData(ExtraData*);
-
 #if INSIDE_BLINK
     BLINK_PLATFORM_EXPORT WebRTCVoidRequest(RTCVoidRequest*);
 #endif
 
 private:
     WebPrivatePtr<RTCVoidRequest> m_private;
 };
 
 } // namespace blink
 
 #endif // WebRTCVoidRequest_h