diff -r 000000000000 -r 6474c204b198 dom/workers/test/atob_worker.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/workers/test/atob_worker.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,46 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+var data = [ -1, 0, 1, 1.5, /* null ,*/ undefined, true, false, "foo",
+             "123456789012345", "1234567890123456", "12345678901234567"];
+
+var str = "";
+for (var i = 0; i < 30; i++) {
+  data.push(str);
+  str += i % 2 ? "b" : "a";
+}
+
+onmessage = function(event) {
+  data.forEach(function(string) {
+    var encoded = btoa(string);
+    postMessage({ type: "btoa", value: encoded });
+    postMessage({ type: "atob", value: atob(encoded) });
+  });
+
+  var threw;
+  try {
+    atob();
+  }
+  catch(e) {
+    threw = true;
+  }
+
+  if (!threw) {
+    throw "atob didn't throw when called without an argument!";
+  }
+  threw = false;
+
+  try {
+    btoa();
+  }
+  catch(e) {
+    threw = true;
+  }
+
+  if (!threw) {
+    throw "btoa didn't throw when called without an argument!";
+  }
+
+  postMessage({ type: "done" });
+}