The Tor Browser / file revision

 function run_test() {

   var Cu = Components.utils;

   sb = new Cu.Sandbox('http://www.example.com');

   sb.do_check_eq = do_check_eq;

   Cu.evalInSandbox('do_check_eq(typeof new Promise(function(resolve){resolve();}), "object");',

                    sb);

   sb = new Cu.Sandbox('http://www.example.com',

                       { wantGlobalProperties: ["-Promise"] });

   sb.do_check_eq = do_check_eq;

   Cu.evalInSandbox('do_check_eq(typeof Promise, "undefined");', sb);

   do_check_eq(typeof new Promise(function(resolve){resolve();}), "object");

 }