Add MD ink drop ripple to app list button

ui/app_list/presenter/app_list_presenter.h

Index: ui/app_list/presenter/app_list_presenter.h
diff --git a/ui/app_list/presenter/app_list_presenter.h b/ui/app_list/presenter/app_list_presenter.h
index cea0c9ba936881b00501cb3cf7b1fd3d25a8a93d..3d864406054f9d215b6a6e0104b750ffd3c5e066 100644
--- a/ui/app_list/presenter/app_list_presenter.h
+++ b/ui/app_list/presenter/app_list_presenter.h
@@ -32,6 +32,9 @@ class APP_LIST_PRESENTER_EXPORT AppListPresenter {
   // 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;