diff -r 000000000000 -r 6474c204b198 dom/workers/test/errorPropagation_worker.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/workers/test/errorPropagation_worker.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,50 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+var seenScopeError;
+onerror = function(message, filename, lineno) {
+  if (!seenScopeError) {
+    seenScopeError = true;
+    postMessage({
+      type: "scope",
+      data: { message: message, filename: filename, lineno: lineno }
+    });
+    return true;
+  }
+};
+
+onmessage = function(event) {
+  var workerId = parseInt(event.data);
+
+  if (workerId > 1) {
+    var worker = new Worker("errorPropagation_worker.js");
+
+    worker.onmessage = function(event) {
+      postMessage(event.data);
+    };
+
+    var seenWorkerError;
+    worker.onerror = function(event) {
+      if (!seenWorkerError) {
+        seenWorkerError = true;
+        postMessage({
+          type: "worker",
+          data: {
+            message: event.message,
+            filename: event.filename,
+            lineno: event.lineno
+          }
+        });
+        event.preventDefault();
+      }
+    };
+
+    worker.postMessage(workerId - 1);
+    return;
+  }
+
+  var interval = setInterval(function() {
+    throw new Error("expectedError");
+  }, 100);
+};