Add language_prefs namespace to language_preferences.h.

chrome/browser/chromeos/language_preferences.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_LANGUAGE_PREFERENCES_H_
 #define CHROME_BROWSER_CHROMEOS_LANGUAGE_PREFERENCES_H_
 #pragma once
 
 #include <stddef.h>  // For size_t
 
 // This file defines types and declare variables used in "Languages and
 // Input" settings in Chromium OS.
 namespace chromeos {
+namespace language_prefs {
 
 // The struct is used for preferences consisting of multiple choices, like
 // punctuation types used in Japanese input method.
 template <typename DataType>
 struct LanguageMultipleChoicePreference {
   const char* pref_name;  // Chrome preference name.
   DataType default_pref_value;
   const char* ibus_config_name;
   // Currently we have 10 combobox items at most.
   static const size_t kMaxItems = 11;
@@ skipping 132 matching lines @@
 
 // A string Chrome preference (Local State) of the preferred keyboard layout in
 // the login screen.
 extern const char kPreferredKeyboardLayout[];
 
 // A input method name that corresponds the hardware keyboard layout.
 // TODO(yusukes): just assuming US qwerty keyboard is not always correct.
 // crosbug.com/5579.
 extern const char kHardwareKeyboardLayout[];
 
+}  // language_prefs
 }  // chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LANGUAGE_PREFERENCES_H_