Allow XHR timeout attribute to be overridden after send(), per spec

LayoutTests/http/tests/xmlhttprequest/workers/resources/xmlhttprequest-timeout-override.js

Index: LayoutTests/http/tests/xmlhttprequest/workers/resources/xmlhttprequest-timeout-override.js
diff --git a/LayoutTests/http/tests/xmlhttprequest/workers/resources/upload-onprogress-event.js b/LayoutTests/http/tests/xmlhttprequest/workers/resources/xmlhttprequest-timeout-override.js
similarity index 67%
copy from LayoutTests/http/tests/xmlhttprequest/workers/resources/upload-onprogress-event.js
copy to LayoutTests/http/tests/xmlhttprequest/workers/resources/xmlhttprequest-timeout-override.js
index d070e0fedf53cec2eb949fb4e904db7ef42f1441..cbaf461ce104d466987e32c4f2c8bdac76fba9cb 100644
--- a/LayoutTests/http/tests/xmlhttprequest/workers/resources/upload-onprogress-event.js
+++ b/LayoutTests/http/tests/xmlhttprequest/workers/resources/xmlhttprequest-timeout-override.js
@@ -1,7 +1,7 @@
 if (window.testRunner) {
     testRunner.dumpAsText();
     testRunner.waitUntilDone();
- }
+}
 
 var console_messages = document.createElement("ul");
 document.body.appendChild(console_messages);
@@ -14,15 +14,16 @@ function log(message)
 }
 
 var progress_ticks = 0;
-var worker = createWorker('resources/upload-onprogress-worker.js');
+var worker = createWorker('resources/xmlhttprequest-timeout-override-worker.js');
+var messages = [];
 worker.onmessage = function(evt)
 {
     if (/log .+/.test(evt.data)) {
-        log(evt.data.substr(4));
-    } else if (/tick .+/.test(evt.data)) {
-        progress_ticks++;
+        var msg = evt.data.substr(4);
+        messages.push(msg);
+        log(msg);
     } else if (/DONE/.test(evt.data)) {
-        log(progress_ticks >= 1 ? "PASS" : "FAIL");
+        log(messages.length === 1 && messages[0] === "timeout" ? "PASS" : "FAIL");
         if (window.testRunner)
             testRunner.notifyDone();
     }