The Tor Browser / file revision

 // Used to test XHR in the worker.

 onconnect = function(e) {

   let port = e.ports[0];

   let req;

   try {

     importScripts("relative_import.js");

     // the import should have exposed "testVar" and "testFunc" from the module.

     if (testVar != "oh hai" || testFunc() != "oh hai") {

       port.postMessage({topic: "done", result: "import worked but global is not available"});

       return;

     }

     // causeError will cause a script error, so that we can check the

     // error location for importScripts'ed files is correct.

     try {

       causeError();

     } catch(e) {

       let fileName = e.fileName;

       if (fileName.startsWith("http") &&

           fileName.endsWith("/relative_import.js") &&

           e.lineNumber == 4)

         port.postMessage({topic: "done", result: "ok"});

       else

         port.postMessage({topic: "done", result: "invalid error location: " + fileName + ":" + e.lineNumber});

       return;

     }

   } catch(e) {

     port.postMessage({topic: "done", result: "FAILED to importScripts, " + e.toString() });

     return;

   }

   port.postMessage({topic: "done", result: "FAILED to importScripts, no exception" });

 }