chromeos: Request screen lock directly from session manager.

chrome/browser/chromeos/power/power_button_controller_delegate_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/chromeos/power/power_button_controller_delegate_chromeos.h"
 
 #include "base/logging.h"
 #include "chrome/browser/chromeos/kiosk_mode/kiosk_mode_settings.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/power_manager_client.h"
+#include "chromeos/dbus/session_manager_client.h"
 
 namespace chromeos {
 
 void PowerButtonControllerDelegateChromeos::RequestLockScreen() {
   // If KioskMode is enabled, if the user attempts to lock the screen via
   // the power button, we instead want to log the user out. This seemed to
   // be the most acceptable replacement for the lock action of the power
   // button for Kiosk mode users.
   if (KioskModeSettings::Get()->IsKioskModeEnabled()) {
     browser::AttemptUserExit();
     return;
   }
 
-  DBusThreadManager::Get()->GetPowerManagerClient()->
-      NotifyScreenLockRequested();
+  DBusThreadManager::Get()->GetSessionManagerClient()->RequestLockScreen();
 }
 
 void PowerButtonControllerDelegateChromeos::RequestShutdown() {
   DBusThreadManager::Get()->GetPowerManagerClient()->RequestShutdown();
 }
 
 }  // namespace chromeos