Cleanup namespace usage in public/platform/Web[A-M]*.h.

public/platform/WebGraphicsContext3DProvider.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:
  *
  *     * 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 18 matching lines @@
  */
 
 #ifndef WebGraphicsContext3DProvider_h
 #define WebGraphicsContext3DProvider_h
 
 #include "WebCommon.h"
 
 class GrContext;
 
 namespace blink {
+
 class WebGraphicsContext3D;
 
 class WebGraphicsContext3DProvider {
 public:
     virtual ~WebGraphicsContext3DProvider() { }
 
     virtual WebGraphicsContext3D* context3d() = 0;
     virtual GrContext* grContext() = 0;
 };
 
 } // namespace blink
 
 #endif