Allow Control+Shift+Q on lock screen.

ash/accelerators/accelerator_controller.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 ASH_ACCELERATORS_ACCELERATOR_CONTROLLER_H_
 #define ASH_ACCELERATORS_ACCELERATOR_CONTROLLER_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 85 matching lines @@
   scoped_ptr<BrightnessControlDelegate> brightness_control_delegate_;
   scoped_ptr<CapsLockDelegate> caps_lock_delegate_;
   scoped_ptr<ImeControlDelegate> ime_control_delegate_;
   scoped_ptr<ScreenshotDelegate> screenshot_delegate_;
   scoped_ptr<VolumeControlDelegate> volume_control_delegate_;
 
   // A map from accelerators to the AcceleratorAction values, which are used in
   // the implementation.
   std::map<ui::Accelerator, int> accelerators_;
 
-  // Actions allowed when the user is not signed in or screen is locked
+  // Actions allowed when the user is not signed in.
   std::set<int> actions_allowed_at_login_screen_;
+  // Actions allowed when the screen is locked.
+  std::set<int> actions_allowed_at_lock_screen_;
 
   DISALLOW_COPY_AND_ASSIGN(AcceleratorController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_ACCELERATORS_ACCELERATOR_CONTROLLER_H_