Add MD ink drop ripple to app list button

ui/app_list/presenter/app_list_presenter.h

 // Copyright 2016 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_APP_LIST_PRESENTER_APP_LIST_PRESENTER_H_
 #define UI_APP_LIST_PRESENTER_APP_LIST_PRESENTER_H_
 
 #include <stdint.h>
 
 #include "ui/app_list/presenter/app_list_presenter_export.h"
@@ skipping 14 matching lines @@
   // be shown.
   virtual void Show(int64_t display_id) = 0;
 
   // Invoked to dismiss app list. This may leave the view open but hidden from
   // the user.
   virtual void Dismiss() = 0;
 
   // Show the app list if it is visible, hide it if it is hidden.
   virtual void ToggleAppList(int64_t display_id) = 0;
 
+  // Returns current visibility of the app list.
+  virtual bool IsVisible() const = 0;
+
   // Returns target visibility. This may differ from IsVisible() if a
   // visibility transition is in progress.
   virtual bool GetTargetVisibility() const = 0;
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_PRESENTER_APP_LIST_PRESENTER_H_