We should use UserID object to identify users instead of username.

chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/ui/webui/options/chromeos/cros_language_options_handler.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 172 matching lines @@
 
 void CrosLanguageOptionsHandler::SetApplicationLocale(
     const std::string& language_code) {
   Profile* profile = Profile::FromWebUI(web_ui());
   user_manager::UserManager* user_manager = user_manager::UserManager::Get();
 
   // Secondary users and public session users cannot change the locale.
   const user_manager::User* user =
       ProfileHelper::Get()->GetUserByProfile(profile);
   if (user &&
-      user->email() == user_manager->GetPrimaryUser()->email() &&
+      user->GetUserID() == user_manager->GetPrimaryUser()->GetUserID() &&
       user->GetType() != user_manager::USER_TYPE_PUBLIC_ACCOUNT) {
     profile->ChangeAppLocale(language_code,
                              Profile::APP_LOCALE_CHANGED_VIA_SETTINGS);
   }
 }
 
 void CrosLanguageOptionsHandler::RestartCallback(const base::ListValue* args) {
   content::RecordAction(UserMetricsAction("LanguageOptions_SignOut"));
   chrome::AttemptUserExit();
 }
@@ skipping 57 matching lines @@
         extension_ime_util::GetExtensionIDFromInputMethodID(input_method_id);
     const extensions::Extension* extension =
         enabled_extensions.GetByID(extension_id);
     if (extension)
       entry->SetString("extensionName", extension->name());
   }
 }
 
 }  // namespace options
 }  // namespace chromeos