Implement cycle window forward/backward by keyboard shortcuts.

ui/aura_shell/shell.h

 // Copyright (c) 2011 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 UI_AURA_SHELL_SHELL_H_
 #define UI_AURA_SHELL_SHELL_H_
 #pragma once
 
 #include <utility>
 #include <vector>
@@ skipping 50 matching lines @@
   // Adds or removes |filter| from the RootWindowEventFilter.
   void AddRootWindowEventFilter(aura::EventFilter* filter);
   void RemoveRootWindowEventFilter(aura::EventFilter* filter);
 
   // Toggles between overview mode and normal mode.
   void ToggleOverview();
 
   // Toggles app list.
   void ToggleAppList();
 
+  // Returns true if the screen is locked.
+  bool IsScreenLocked() const;
+
   ShellAcceleratorController* accelerator_controller() {
     return accelerator_controller_.get();
   }
 
   ShellTooltipManager* tooltip_manager() {
     return tooltip_manager_.get();
   }
 
   ShellDelegate* delegate() { return delegate_.get(); }
   Launcher* launcher() { return launcher_.get(); }
@@ skipping 36 matching lines @@
   scoped_ptr<internal::ShellAcceleratorFilter> accelerator_filter_;
 
   scoped_ptr<ShellTooltipManager> tooltip_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };
 
 }  // namespace aura_shell
 
 #endif  // UI_AURA_SHELL_SHELL_H_