Move event handler to window_selector to ensure correct lifetime.

ash/wm/overview/window_selector.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_OVERVIEW_WINDOW_SELECTOR_H_
 #define ASH_WM_OVERVIEW_WINDOW_SELECTOR_H_
 
 #include <vector>
 
 #include "ash/ash_export.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "base/timer/timer.h"
 #include "ui/aura/client/activation_change_observer.h"
 #include "ui/aura/window_observer.h"
 
 namespace aura {
 class RootWindow;
 }
 
 namespace ui {
-class LocatedEvent;
+class EventHandler;
 }
 
 namespace ash {
 
 namespace internal {
 class WindowSelectorTest;
 }
 
 class WindowOverview;
 class WindowSelectorDelegate;
@@ skipping 60 matching lines @@
   // |focus|, restores focus to the stored window.
   void ResetFocusRestoreWindow(bool focus);
 
   // The collection of windows in the overview wrapped by a helper class which
   // restores their state and helps transform them to other root windows.
   ScopedVector<WindowSelectorWindow> windows_;
 
   // The window selection mode.
   Mode mode_;
 
+  // An event handler listening for the release of the alt key during alt-tab
+  // cycling.
+  scoped_ptr<ui::EventHandler> event_handler_;
+
   base::DelayTimer<WindowSelector> start_overview_timer_;
   scoped_ptr<WindowOverview> window_overview_;
 
   // Weak pointer to the selector delegate which will be called when a
   // selection is made.
   WindowSelectorDelegate* delegate_;
 
   // Index of the currently selected window if the mode is CYCLE.
   size_t selected_window_;
 
   // A weak pointer to the window which was focused on entering overview mode.
   // If overview mode is canceled the focus should be restored to this window.
   aura::Window* restore_focus_window_;
 
   // True when restoring focus to the window. This is used to prevent handling
   // the resulting activation.
   bool restoring_focus_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowSelector);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_OVERVIEW_WINDOW_SELECTOR_H_