Enable XHR upload progress events for Workers.

LayoutTests/http/tests/xmlhttprequest/workers/resources/upload-onprogress-event.js

 if (window.testRunner) {
     testRunner.dumpAsText();
     testRunner.waitUntilDone();
  }
 
 var console_messages = document.createElement("ul");
 document.body.appendChild(console_messages);
 
 function log(message)
 {
     var item = document.createElement("li");
     item.appendChild(document.createTextNode(message));
     console_messages.appendChild(item);
 }
 
-var worker = createWorker('resources/xmlhttprequest-file-not-found.js');
+var progress_ticks = 0;
+var worker = createWorker('resources/upload-onprogress-worker.js');
 worker.onmessage = function(evt)
 {
-    if (/log .+/.test(evt.data))
+    if (/log .+/.test(evt.data)) {
         log(evt.data.substr(4));
-    else if (/DONE/.test(evt.data)) {
-        log("PASS");
+    } else if (/tick .+/.test(evt.data)) {
+        progress_ticks++;
+    } else if (/DONE/.test(evt.data)) {
+        log(progress_ticks >= 1 ? "PASS" : "FAIL");
         if (window.testRunner)
             testRunner.notifyDone();
     }
 }