cros: Use SessionController for lock starting code

ash/wm/lock_state_controller.cc

 // Copyright 2013 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 "ash/wm/lock_state_controller.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 
@@ skipping 163 matching lines @@
       SessionStateAnimator::ANIMATION_GRAYSCALE_BRIGHTNESS,
       SessionStateAnimator::ANIMATION_SPEED_SHUTDOWN);
   StartRealShutdownTimer(true);
 }
 
 void LockStateController::OnLockScreenHide(base::Closure callback) {
   StartUnlockAnimationBeforeUIDestroyed(callback);
 }
 
 void LockStateController::SetLockScreenDisplayedCallback(
-    const base::Closure& callback) {
-  lock_screen_displayed_callback_ = callback;
+    base::OnceClosure callback) {
+  DCHECK(lock_screen_displayed_callback_.is_null());
+  lock_screen_displayed_callback_ = std::move(callback);
 }
 
 void LockStateController::OnHostCloseRequested(
     const aura::WindowTreeHost* host) {
   Shell::Get()->shell_delegate()->Exit();
 }
 
 void LockStateController::OnChromeTerminating() {
   // If we hear that Chrome is exiting but didn't request it ourselves, all we
   // can really hope for is that we'll have time to clear the screen.
@@ skipping 293 matching lines @@
                          &LockStateController::OnLockFailTimeout);
 
   lock_duration_timer_.reset(new base::ElapsedTimer());
 }
 
 void LockStateController::PostLockAnimationFinished() {
   animating_lock_ = false;
   VLOG(1) << "PostLockAnimationFinished";
   ShellPort::Get()->OnLockStateEvent(
       LockStateObserver::EVENT_LOCK_ANIMATION_FINISHED);
-  if (!lock_screen_displayed_callback_.is_null()) {
-    lock_screen_displayed_callback_.Run();
-    lock_screen_displayed_callback_.Reset();
-  }
+  if (!lock_screen_displayed_callback_.is_null())
+    std::move(lock_screen_displayed_callback_).Run();
+
   CHECK(!views::MenuController::GetActiveInstance());
   if (shutdown_after_lock_) {
     shutdown_after_lock_ = false;
     StartLockToShutdownTimer();
   }
 }
 
 void LockStateController::UnlockAnimationAfterUIDestroyedFinished() {
   RestoreUnlockedProperties();
 }
@@ skipping 39 matching lines @@
     SessionStateAnimator::AnimationSpeed speed,
     SessionStateAnimator::AnimationSequence* animation_sequence) {
   if (unlocked_properties_.get() && unlocked_properties_->wallpaper_is_hidden) {
     animation_sequence->StartAnimation(SessionStateAnimator::WALLPAPER,
                                        SessionStateAnimator::ANIMATION_FADE_OUT,
                                        speed);
   }
 }
 
 }  // namespace ash