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

chrome/browser/automation/testing_automation_provider_chromeos.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/automation/testing_automation_provider.h"
 
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/system/tray/system_tray_delegate.h"
 #include "base/command_line.h"
@@ skipping 455 matching lines @@
 
   chromeos::ScreenLocker* screen_locker =
       chromeos::ScreenLocker::default_screen_locker();
   if (!screen_locker) {
     AutomationJSONReply(this, reply_message).SendError(
         "No default screen locker. Are you sure the screen is locked?");
     return;
   }
 
   new ScreenUnlockObserver(this, reply_message);
-  screen_locker->Authenticate(ASCIIToUTF16(password));
+  screen_locker->AuthenticateByPassword(password);
 }
 
 // Signing out could have undesirable side effects: session_manager is
 // killed, so its children, including chrome and the window manager, will
 // also be killed. Anything owned by chronos will probably be killed.
 void TestingAutomationProvider::SignoutInScreenLocker(
     DictionaryValue* args, IPC::Message* reply_message) {
   AutomationJSONReply reply(this, reply_message);
   chromeos::ScreenLocker* screen_locker =
       chromeos::ScreenLocker::default_screen_locker();
@@ skipping 780 matching lines @@
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       AddObserver(power_manager_observer_);
 }
 
 void TestingAutomationProvider::RemoveChromeosObservers() {
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
       RemoveObserver(power_manager_observer_);
   delete power_manager_observer_;
   power_manager_observer_ = NULL;
 }