Add more missing closing namespace comments.

third_party/WebKit/Source/core/html/HTMLRubyElement.h

 // 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.
 
 #ifndef HTMLRubyElement_h
 #define HTMLRubyElement_h
 
 #include "core/html/HTMLElement.h"
 
 namespace blink {
 
 // <ruby> is an HTMLElement in script, but we use a separate interface here
 // so HTMLElement's createLayoutObject doesn't need to know about it.
 class HTMLRubyElement final : public HTMLElement {
 public:
     DECLARE_NODE_FACTORY(HTMLRubyElement);
 
 private:
     explicit HTMLRubyElement(Document&);
 
     LayoutObject* createLayoutObject(const ComputedStyle&) override;
 };
 
-} // namespace
+} // namespace blink
 
 #endif