Cleanup namespace usage in platform/graphics/[G-S]*

Source/platform/graphics/ImageBufferClient.h

 /*
  * Copyright (c) 2014, 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 23 matching lines @@
 namespace blink {
 
 class ImageBufferClient {
 public:
     virtual ~ImageBufferClient() { }
     virtual void notifySurfaceInvalid() = 0;
     virtual bool isDirty() = 0;
     virtual void didFinalizeFrame() = 0;
 };
 
-}
+} // namespace blink
 
 #endif