The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 XPCOMUtils.defineLazyModuleGetter(this, "SelectContentHelper",

                                   "resource://gre/modules/SelectContentHelper.jsm");

 addEventListener("mozshowdropdown", event => {

   if (!event.isTrusted)

     return;

   new SelectContentHelper(event.target, this);

 });