cros: Use SessionController for lock starting code

chrome/browser/chromeos/login/lock/screen_locker.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_LOCK_SCREEN_LOCKER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_LOCK_SCREEN_LOCKER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 127 matching lines @@
 
   // Called when screen locker is safe to delete.
   static void ScheduleDeletion();
 
   // Returns true if |account_id| is found among logged in users.
   bool IsUserLoggedIn(const AccountId& account_id) const;
 
   // Looks up user in unlock user list.
   const user_manager::User* FindUnlockUser(const AccountId& account_id);
 
+  // Callback to be invoked for ash start lock request. |locked| is true when
+  // ash is fully locked and post lock animation finishes. Otherwise, the start
+  // lock request is failed.
+  void OnStartLockCallback(bool locked);
+
   // WebUIScreenLocker instance in use.
   std::unique_ptr<WebUIScreenLocker> web_ui_;
 
   // Users that can unlock the device.
   user_manager::UserList users_;
 
   // Used to authenticate the user to unlock.
   scoped_refptr<Authenticator> authenticator_;
 
   // Used to authenticate the user to unlock supervised users.
@@ skipping 33 matching lines @@
   scoped_refptr<input_method::InputMethodManager::State> saved_ime_state_;
 
   base::WeakPtrFactory<ScreenLocker> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenLocker);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_LOCK_SCREEN_LOCKER_H_