Use overview mode for alt-tab cycling.

ash/wm/window_selector_controller.h

 // 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.
 
 #ifndef ASH_WM_WINDOW_SELECTOR_CONTROLLER_H_
 #define ASH_WM_WINDOW_SELECTOR_CONTROLLER_H_
 
 #include <list>
 #include <vector>
 
 #include "ash/ash_export.h"
+#include "ash/wm/window_selector.h"
 #include "ash/wm/window_selector_delegate.h"
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/window_observer.h"
 
 namespace aura {
 class Window;
 }
 
+namespace ui {
+class EventHandler;
+}
+
 namespace ash {
 
 class WindowSelector;
 
 // Manages a window selector which displays an overview of all windows and
 // allows selecting a window to activate it.
 class ASH_EXPORT WindowSelectorController
     : public WindowSelectorDelegate {
  public:
   WindowSelectorController();
   virtual ~WindowSelectorController();
 
   // Returns true if selecting windows in an overview is enabled. This is false
   // at certain times, such as when the lock screen is visible.
   static bool CanSelect();
 
   // Enters overview mode. This is essentially the window cycling mode however
   // not released on releasing the alt key and allows selecting with the mouse
   // or touch rather than keypresses.
   void ToggleOverview();
 
+  // Cycles between windows in the given |direction|. It is assumed that the
+  // alt key is held down and a key filter is installed to watch for alt being
+  // released.
+  void HandleCycleWindow(WindowSelector::Direction direction);
+
+  // Informs the controller that the Alt key has been released and it can
+  // terminate the existing multi-step cycle.
+  void AltKeyReleased();
+
   // Returns true if window selection mode is active.
   bool IsSelecting();
 
   // WindowSelectorDelegate:
   virtual void OnWindowSelected(aura::Window* window) OVERRIDE;
   virtual void OnSelectionCanceled() OVERRIDE;
 
  private:
   scoped_ptr<WindowSelector> window_selector_;
+  scoped_ptr<ui::EventHandler> event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowSelectorController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_WINDOW_SELECTOR_CONTROLLER_H_