Add more missing closing namespace comments.

third_party/WebKit/Source/core/page/ContextMenuClient.h

 /*
  * Copyright (C) 2006 Apple Computer, 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 19 matching lines @@
 
 class ContextMenu;
 
 class ContextMenuClient {
 public:
     virtual ~ContextMenuClient() { }
     virtual void showContextMenu(const ContextMenu*) = 0;
     virtual void clearContextMenu() = 0;
 };
 
-}
+} // namespace blink
 
 #endif