The Tor Browser / file revision

 var t = async_test(document.title);

 var frameLoadsPending = 2;

 var callMasterFrame = true;

 var testDone = false;

 var masterFrameOrigin = "";

 var slaveFrameOrigin = "";

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

 const framePath = "/tests/dom/tests/mochitest/localstorage/";

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

 function onMessageReceived(event)

 {

   switch (event.data)

   {

     // Indication of the frame onload event

     case "frame loaded":

       if (--frameLoadsPending)

         break;

       // Just fall through...

     // Indication of successfully finished step of a test

     case "perf":

       if (callMasterFrame)

         masterFrame.postMessage("step", masterFrameOrigin);

       else

         slaveFrame.postMessage("step", slaveFrameOrigin);

       callMasterFrame = !callMasterFrame;

       break;

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

     case "done":

       if (testDone)

         break;

       testDone = true;

       t.done();

       break;

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

     default:

       t.step(function() {

         assert_true(!event.data.match(failureRegExp), event.data);

       });

       break;

   }

 }