The Tor Browser / file revision

 var slaveLoadsPending = 1;

 var slaveOrigin = "";

 var slave = null;

 var failureRegExp = new RegExp("^FAILURE");

 const slavePath = "/tests/dom/tests/mochitest/sessionstorage/";

 window.addEventListener("message", onMessageReceived, false);

 function onMessageReceived(event)

 {

   //alert("master got event: "+event.data);

   switch (event.data)

   {

     // Indication of the frame onload event

     case "frame loaded":

       if (--slaveLoadsPending)

         break;

       // Just fall through...

     // Indication of successfully finished step of a test

     case "perf":

       // We called doStep before the frame was load

       if (event.data == "perf")

         doStep();

       slave.postMessage("step", slaveOrigin);

       break;

     // Indication of all test parts finish (from any of the frames)

     case "done":

       sessionStorage.clear();

       slaveLoadsPending = 1;

       doNextTest();

       break;

     // Any other message indicates error or succes message of a test

     default:

       SimpleTest.ok(!event.data.match(failureRegExp), event.data);

       break;

   }

 }