Add chromeos namespace to the language options page and its friends.

chrome/browser/chromeos/dom_ui/language_chewing_options_handler.h

 // Copyright (c) 2010 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 CHROME_BROWSER_CHROMEOS_DOM_UI_LANGUAGE_CHEWING_OPTIONS_HANDLER_H_
 #define CHROME_BROWSER_CHROMEOS_DOM_UI_LANGUAGE_CHEWING_OPTIONS_HANDLER_H_
 #pragma once
 
 #include "chrome/browser/dom_ui/options_ui.h"
 
 class DictionaryValue;
 
+namespace chromeos {
+
 // Chewing options page UI handler.
 class LanguageChewingOptionsHandler : public OptionsPageUIHandler {
  public:
   LanguageChewingOptionsHandler();
   virtual ~LanguageChewingOptionsHandler();
 
   // OptionsUIHandler implementation.
   virtual void GetLocalizedValues(DictionaryValue* localized_strings);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LanguageChewingOptionsHandler);
 };
 
+}  // namespace chromeos
+
 #endif  // CHROME_BROWSER_CHROMEOS_DOM_UI_LANGUAGE_CHEWING_OPTIONS_HANDLER_H_