Made possible to lock and unlock with several logged in users.

chrome/browser/chromeos/login/webui_screen_locker.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_WEBUI_SCREEN_LOCKER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_WEBUI_SCREEN_LOCKER_H_
 
 #include <string>
 
 #include "ash/wm/session_state_observer.h"
@@ skipping 33 matching lines @@
                           public ScreenLockerDelegate,
                           public LockWindow::Observer,
                           public ash::SessionStateObserver,
                           public views::WidgetObserver,
                           public PowerManagerClient::Observer,
                           public content::WebContentsObserver {
  public:
   explicit WebUIScreenLocker(ScreenLocker* screen_locker);
 
   // ScreenLockerDelegate implementation.
-  virtual void LockScreen(bool unlock_on_input) OVERRIDE;
+  virtual void LockScreen() OVERRIDE;
   virtual void ScreenLockReady() OVERRIDE;
   virtual void OnAuthenticate() OVERRIDE;
   virtual void SetInputEnabled(bool enabled) OVERRIDE;
   virtual void ShowErrorMessage(
       int error_msg_id,
       HelpAppLauncher::HelpTopic help_topic_id) OVERRIDE;
   virtual void ClearErrors() OVERRIDE;
   virtual void AnimateAuthenticationSuccess() OVERRIDE;
   virtual gfx::NativeWindow GetNativeWindow() const OVERRIDE;
   virtual content::WebUI* GetAssociatedWebUI() OVERRIDE;
@@ skipping 69 matching lines @@
   base::TimeTicks lock_time_;
 
   base::WeakPtrFactory<WebUIScreenLocker> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebUIScreenLocker);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_WEBUI_SCREEN_LOCKER_H_