diff -r 000000000000 -r 6474c204b198 dom/workers/test/threadTimeouts_worker.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/workers/test/threadTimeouts_worker.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,44 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+var gTimeoutId;
+var gTimeoutCount = 0;
+var gIntervalCount = 0;
+
+function timeoutFunc() {
+  if (++gTimeoutCount > 1) {
+    throw new Error("Timeout called more than once!");
+  }
+  postMessage("timeoutFinished");
+}
+
+function intervalFunc() {
+  if (++gIntervalCount == 2) {
+    postMessage("intervalFinished");
+  }
+}
+
+function messageListener(event) {
+  switch (event.data) {
+    case "startTimeout":
+      gTimeoutId = setTimeout(timeoutFunc, 2000);
+      clearTimeout(gTimeoutId);
+      gTimeoutId = setTimeout(timeoutFunc, 2000);
+      break;
+    case "startInterval":
+      gTimeoutId = setInterval(intervalFunc, 2000);
+      break;
+    case "cancelInterval":
+      clearInterval(gTimeoutId);
+      postMessage("intervalCanceled");
+      break;
+    case "startExpression":
+      setTimeout("this.postMessage('expressionFinished');", 2000);
+      break;
+    default:
+      throw "Bad message: " + event.data;
+  }
+}
+
+addEventListener("message", messageListener, false);