Add more missing closing namespace comments.

third_party/WebKit/Source/modules/webaudio/AudioBufferCallback.h

 /*
  * 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:
  * 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 23 matching lines @@
 class DOMException;
 
 class AudioBufferCallback : public GarbageCollectedFinalized<AudioBufferCallback> {
 public:
     virtual ~AudioBufferCallback() { }
     DEFINE_INLINE_VIRTUAL_TRACE() { }
     virtual void handleEvent(AudioBuffer*) = 0;
     virtual void handleEvent(DOMException*) = 0;
 };
 
-} // namespace
+} // namespace blink
 
 #endif // AudioBufferCallback_h