ash: Update app list button.

ash/launcher/app_list_button.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_LAUNCHER_APP_LIST_BUTTON_H_
 #define ASH_LAUNCHER_APP_LIST_BUTTON_H_
 
+#include "ash/wm/app_list_controller_observer.h"
 #include "ui/views/controls/button/image_button.h"
 
 namespace ash {
 namespace internal {
 
 class LauncherButtonHost;
 
 // Button used for the AppList icon on the launcher.
-class AppListButton : public views::ImageButton {
+class AppListButton : public views::ToggleImageButton,
+                      public AppListControllerObserver {
  public:
   AppListButton(views::ButtonListener* listener,
                 LauncherButtonHost* host);
   virtual ~AppListButton();
 
   void StartLoadingAnimation();
   void StopLoadingAnimation();
 
  protected:
   // View overrides:
   virtual bool OnMousePressed(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseReleased(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseCaptureLost() OVERRIDE;
   virtual bool OnMouseDragged(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseMoved(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseEntered(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnMouseExited(const ui::MouseEvent& event) OVERRIDE;
   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
 
  private:
+  // AppListControllerObserver overrides:
+  virtual void OnAppLauncherVisibilityChanged(
+      bool visible,
+      const aura::RootWindow* root_window) OVERRIDE;
+
   LauncherButtonHost* host_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListButton);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_LAUNCHER_APP_LIST_BUTTON_H_