Add more missing closing namespace comments.

third_party/WebKit/Source/web/PopupMenuImpl.h

 // Copyright (c) 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.
 
 #ifndef PopupMenuImpl_h
 #define PopupMenuImpl_h
 
 #include "core/page/PagePopupClient.h"
 #include "platform/PopupMenu.h"
 
@@ skipping 41 matching lines @@
     Element& ownerElement() override;
     Locale& locale() override;
     void didClosePopup() override;
 
     RawPtrWillBeMember<ChromeClientImpl> m_chromeClient;
     RawPtrWillBeMember<HTMLSelectElement> m_ownerElement;
     PagePopup* m_popup;
     bool m_needsUpdate;
 };
 
-}
+} // namespace blink
 
 #endif // PopupMenuImpl_h