ui/file_manager/externs/menu_item_update_event.js

// Copyright 2017 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.

class MenuItemUpdateEvent extends Event {
  constructor() {
    /**
     * @type {!cr.ui.MenuButton}
     */
    this.menuButton;
  }
}