Fix virtual/override/final usage in Source/modules/.

Source/modules/mediastream/MediaStreamTrackSourcesRequestImpl.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 23 matching lines @@
 class ExecutionContext;
 class MediaStreamTrackSourcesCallback;
 class WebSourceInfo;
 template<typename T> class WebVector;
 
 class MediaStreamTrackSourcesRequestImpl final : public MediaStreamTrackSourcesRequest {
 public:
     static MediaStreamTrackSourcesRequestImpl* create(ExecutionContext&, MediaStreamTrackSourcesCallback*);
     ~MediaStreamTrackSourcesRequestImpl();
 
-    virtual String origin() override;
-    virtual void requestSucceeded(const WebVector<WebSourceInfo>&) override;
+    String origin() override;
+    void requestSucceeded(const WebVector<WebSourceInfo>&) override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     MediaStreamTrackSourcesRequestImpl(ExecutionContext&, MediaStreamTrackSourcesCallback*);
 
     void performCallback();
 
     Member<MediaStreamTrackSourcesCallback> m_callback;
     RefPtrWillBeMember<ExecutionContext> m_executionContext;
     SourceInfoVector m_sourceInfos;
 };
 
 } // namespace blink
 
 #endif // MediaStreamTrackSourcesRequestImpl_h