The Tor Browser / file revision

 /* Any copyright is dedicated to the Public Domain.

    http://creativecommons.org/publicdomain/zero/1.0/ */

 const { classes: Cc, interfaces: Ci, results: Cr, utils: Cu } = Components;

 const { Services } = Cu.import('resource://gre/modules/Services.jsm');

 const { SystemAppProxy } = Cu.import('resource://gre/modules/SystemAppProxy.jsm');

 addMessageListener('init-chrome-event', function(message) {

   // listen mozChromeEvent and forward to content process.

   let type = message.type;

   SystemAppProxy.addEventListener('mozChromeEvent', function(event) {

     let details = event.detail;

     if (details.type === type) {

       sendAsyncMessage('chrome-event', details);

     }

   }, true);

 });