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

Source/platform/graphics/ImageSource.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp.toker@collabora.co.uk>
  * Copyright (C) 2008, 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.
@@ skipping 153 matching lines @@
     return m_decoder && m_decoder->frameIsCompleteAtIndex(index);
 }
 
 unsigned ImageSource::frameBytesAtIndex(size_t index) const
 {
     if (!m_decoder)
         return 0;
     return m_decoder->frameBytesAtIndex(index);
 }
 
-}
+} // namespace blink