Add more missing closing namespace comments.

third_party/WebKit/Source/core/html/track/AudioTrack.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/html/track/AudioTrack.h"
 
 #include "core/html/HTMLMediaElement.h"
 
 namespace blink {
 
@@ skipping 69 matching lines @@
         || (kind == translationKeyword())
         || (kind == commentaryKeyword())
         || (kind == emptyAtom);
 }
 
 AtomicString AudioTrack::defaultKind() const
 {
     return emptyAtom;
 }
 
-}
+} // namespace blink