Add more missing closing namespace comments.

third_party/WebKit/Source/core/html/ImageDocument.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple 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 75 matching lines @@
 
     enum ShrinkToFitMode {
         Viewport,
         Desktop
     };
     ShrinkToFitMode m_shrinkToFitMode;
 };
 
 DEFINE_DOCUMENT_TYPE_CASTS(ImageDocument);
 
-}
+} // namespace blink
 
 #endif // ImageDocument_h