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

chrome/browser/chromeos/dom_ui/language_options_handler.h

Index: chrome/browser/chromeos/dom_ui/language_options_handler.h
diff --git a/chrome/browser/chromeos/dom_ui/language_options_handler.h b/chrome/browser/chromeos/dom_ui/language_options_handler.h
index 73441fa998b619e15213b85af05c5c89586e0c4f..d8a957a57c5d5bac08bfcc043633c9e9e526d121 100644
--- a/chrome/browser/chromeos/dom_ui/language_options_handler.h
+++ b/chrome/browser/chromeos/dom_ui/language_options_handler.h
@@ -11,6 +11,8 @@
 class DictionaryValue;
 class ListValue;
 
+namespace chromeos {
+
 // ChromeOS language options page UI handler.
 class LanguageOptionsHandler : public OptionsPageUIHandler {
  public:
@@ -40,4 +42,6 @@ class LanguageOptionsHandler : public OptionsPageUIHandler {
   DISALLOW_COPY_AND_ASSIGN(LanguageOptionsHandler);
 };
 
+}  // namespace
+
 #endif  // CHROME_BROWSER_CHROMEOS_DOM_UI_LANGUAGE_OPTIONS_HANDLER_H_