Revert of ChromeOS NetworkScreenHandler should not call CheckAndResolveLocale on UI thread.

chrome/browser/chromeos/login/session/user_session_manager.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 CHROME_BROWSER_CHROMEOS_LOGIN_SESSION_USER_SESSION_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SESSION_USER_SESSION_MANAGER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 129 matching lines @@
       std::string* chrome_client_secret);
   void SetAppModeChromeClientOAuthInfo(
       const std::string& chrome_client_id,
       const std::string& chrome_client_secret);
 
   // Changes browser locale (selects best suitable locale from different
   // user settings). Returns true if callback will be called.
   bool RespectLocalePreference(
       Profile* profile,
       const user_manager::User* user,
-      const locale_util::SwitchLanguageCallback& callback) const;
+      scoped_ptr<locale_util::SwitchLanguageCallback> callback) const;
 
   // Returns true if Easy unlock keys needs to be updated.
   bool NeedsToUpdateEasyUnlockKeys() const;
 
   // Returns true if there are pending Easy unlock key operations and
   // |callback| will be invoked when it is done.
   bool CheckEasyUnlockKeyOps(const base::Closure& callback);
 
   void AddSessionStateObserver(chromeos::UserSessionStateObserver* observer);
   void RemoveSessionStateObserver(chromeos::UserSessionStateObserver* observer);
@@ skipping 151 matching lines @@
   scoped_ptr<EasyUnlockKeyManager> easy_unlock_key_manager_;
   bool running_easy_unlock_key_ops_;
   base::Closure easy_unlock_key_ops_finished_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(UserSessionManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SESSION_USER_SESSION_MANAGER_H_