Add more missing closing namespace comments.

third_party/WebKit/Source/core/dom/DocumentLifecycle.cpp

 /*
  * Copyright (C) 2013 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 304 matching lines @@
         DEBUG_STRING_CASE(Stopping);
         DEBUG_STRING_CASE(Stopped);
         DEBUG_STRING_CASE(Disposed);
     }
 
     ASSERT_NOT_REACHED();
     return "Unknown";
 }
 #endif
 
-}
+} // namespace blink