Cleanup redundant namespace usage in Source/platform

Source/platform/mediastream/RTCSessionDescriptionRequest.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:
  *
  * 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
@@ skipping 19 matching lines @@
 
 #ifndef RTCSessionDescriptionRequest_h
 #define RTCSessionDescriptionRequest_h
 
 #include "wtf/PassOwnPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 class WebRTCSessionDescription;
-}
-
-namespace blink {
 
 class RTCSessionDescriptionRequest : public RefCounted<RTCSessionDescriptionRequest> {
 public:
     class ExtraData {
     public:
         virtual ~ExtraData() { }
     };
 
     virtual ~RTCSessionDescriptionRequest() { }
 
-    virtual void requestSucceeded(const blink::WebRTCSessionDescription&) = 0;
+    virtual void requestSucceeded(const WebRTCSessionDescription&) = 0;
     virtual void requestFailed(const String& error) = 0;
 
     ExtraData* extraData() const { return m_extraData.get(); }
     void setExtraData(PassOwnPtr<ExtraData> extraData) { m_extraData = extraData; }
 
 protected:
     RTCSessionDescriptionRequest() { }
 
 private:
     OwnPtr<ExtraData> m_extraData;
 };
 
 } // namespace blink
 
 #endif // RTCSessionDescriptionRequest_h