Devirtualize several mediastream class destructors

Source/modules/mediastream/MediaStreamTrackSourcesRequest.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 33 matching lines @@
 class ExecutionContext;
 
 class MediaStreamTrackSourcesRequest : public RefCounted<MediaStreamTrackSourcesRequest> {
 public:
     class ExtraData : public RefCounted<ExtraData> {
     public:
         virtual ~ExtraData() { }
     };
 
     static PassRefPtr<MediaStreamTrackSourcesRequest> create(ExecutionContext*, PassRefPtr<MediaStreamTrackSourcesCallback>);
-    virtual ~MediaStreamTrackSourcesRequest();
+    ~MediaStreamTrackSourcesRequest();
 
     String origin() { return m_origin; }
 
     void requestSucceeded(const WebKit::WebVector<WebKit::WebSourceInfo>&);
 
     PassRefPtr<ExtraData> extraData() const { return m_extraData; }
     void setExtraData(PassRefPtr<ExtraData> extraData) { m_extraData = extraData; }
 
 private:
     MediaStreamTrackSourcesRequest(ExecutionContext*, PassRefPtr<MediaStreamTrackSourcesCallback>);
 
     void scheduledEventTimerFired(Timer<MediaStreamTrackSourcesRequest>*);
 
     RefPtr<MediaStreamTrackSourcesCallback> m_callback;
     RefPtr<ExtraData> m_extraData;
     String m_origin;
     Timer<MediaStreamTrackSourcesRequest> m_scheduledEventTimer;
     SourceInfoVector m_sourceInfos;
     RefPtr<MediaStreamTrackSourcesRequest> m_protect;
 };
 
 } // namespace WebCore
 
 #endif // MediaStreamTrackSourcesRequest_h