Do not start autoshutdown on lock button press.

ash/wm/session_state_controller.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 "ash/wm/session_state_controller.h"
 
 #include "ash/ash_switches.h"
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/shell_window_ids.h"
@@ skipping 119 matching lines @@
 }
 
 void SessionStateController::StartLockAnimationAndLockImmediately() {
   animator_->ShowBlackLayer();
   animator_->StartAnimation(
       internal::SessionStateAnimator::NON_LOCK_SCREEN_CONTAINERS,
       internal::SessionStateAnimator::ANIMATION_SLOW_CLOSE);
   OnLockTimeout();
 }
 
-void SessionStateController::StartLockAnimation() {
-  shutdown_after_lock_ = true;
+void SessionStateController::StartLockAnimation(bool shutdown_after_lock) {
+  shutdown_after_lock_ = shutdown_after_lock;
 
   animator_->ShowBlackLayer();
   animator_->StartAnimation(
       internal::SessionStateAnimator::NON_LOCK_SCREEN_CONTAINERS,
       internal::SessionStateAnimator::ANIMATION_SLOW_CLOSE);
   StartLockTimer();
 }
 
 void SessionStateController::StartShutdownAnimation() {
   animator_->ShowBlackLayer();
@@ skipping 198 matching lines @@
     if (delegate) {
       delegate->Exit();
       return;
     }
   }
 #endif
   delegate_->RequestShutdown();
 }
 
 }  // namespace ash