diff -r 000000000000 -r 6474c204b198 dom/workers/test/timeoutTracing_worker.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/workers/test/timeoutTracing_worker.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,13 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+onmessage = function(event) {
+  throw "No messages should reach me!";
+}
+
+setInterval(function() { postMessage("Still alive!"); }, 20);
+setInterval(";", 20);
+
+postMessage("Begin!");