Add more missing closing namespace comments.

third_party/WebKit/Source/platform/testing/UnitTestHelpers.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:
  *
  * 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
@@ skipping 65 matching lines @@
 void enterRunLoop()
 {
     base::MessageLoop::current()->Run();
 }
 
 void exitRunLoop()
 {
     base::MessageLoop::current()->QuitWhenIdle();
 }
 
-}
-}
+} // namespace testing
+} // namespace blink