Cleanup namespace usage in public/platform/{Web[P-W]*,linux/*}.h

public/platform/WebRTCDTMFSenderHandler.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 12 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WebRTCDTMFSenderHandler_h
 #define WebRTCDTMFSenderHandler_h
 
 #include "WebCommon.h"
 #include "WebString.h"
 
 namespace blink {
+
 class WebRTCDTMFSenderHandlerClient;
 
 class WebRTCDTMFSenderHandler {
 public:
     virtual ~WebRTCDTMFSenderHandler() { }
 
     virtual void setClient(WebRTCDTMFSenderHandlerClient*) = 0;
 
     virtual WebString currentToneBuffer() = 0;
 
     virtual bool canInsertDTMF() = 0;
     virtual bool insertDTMF(const WebString& tones, long duration, long interToneGap) = 0;
 };
 
 } // namespace blink
 
 #endif // WebRTCDTMFSenderHandler_h