Add more missing closing namespace comments.

third_party/WebKit/Source/platform/mhtml/MHTMLArchive.cpp

 /*
  * Copyright (C) 2011 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 252 matching lines @@
     m_subframeArchives.append(subframeArchive);
 }
 
 DEFINE_TRACE(MHTMLArchive)
 {
     visitor->trace(m_mainResource);
     visitor->trace(m_subresources);
     visitor->trace(m_subframeArchives);
 }
 
-}
+} // namespace blink