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

chrome/browser/chromeos/login/screen_locker_delegate.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_SCREEN_LOCKER_DELEGATE_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_SCREEN_LOCKER_DELEGATE_H_
 
 #include "base/string16.h"
 #include "chrome/browser/chromeos/login/help_app_launcher.h"
 #include "ui/gfx/native_widget_types.h"
 
 class GURL;
 
 namespace content {
 class WebUI;
 }
 
 namespace chromeos {
 
 class ScreenLocker;
 
 // ScreenLockerDelegate takes care of displaying the lock screen UI.
 class ScreenLockerDelegate {
  public:
   explicit ScreenLockerDelegate(ScreenLocker* screen_locker);
   virtual ~ScreenLockerDelegate();
 
   // Initialize the screen locker delegate. This will call ScreenLockReady when
   // done to notify ScreenLocker.
-  virtual void LockScreen(bool unlock_on_input) = 0;
+  virtual void LockScreen() = 0;
 
   // Inform the screen locker that the screen has been locked
   virtual void ScreenLockReady();
 
   // This function is called when ScreenLocker::Authenticate is called to
   // attempt to authenticate with a given password.
   virtual void OnAuthenticate() = 0;
 
   // Enable/disable password input.
   virtual void SetInputEnabled(bool enabled) = 0;
@@ skipping 12 matching lines @@
   // Must call ScreenLocker::UnlockOnLoginSuccess() once all effects are done.
   virtual void AnimateAuthenticationSuccess() = 0;
 
   // Returns the native window displaying the lock screen.
   virtual gfx::NativeWindow GetNativeWindow() const = 0;
 
   // Returns WebUI associated with screen locker implementation or NULL if
   // there isn't one.
   virtual content::WebUI* GetAssociatedWebUI();
 
+  // Returns screen locker associated with delegate.
+  ScreenLocker* screen_locker() { return screen_locker_; }
+
  protected:
   // ScreenLocker that owns this delegate.
   ScreenLocker* screen_locker_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenLockerDelegate);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_SCREEN_LOCKER_DELEGATE_H_