<html>
<head>
  <title>A popup!</title>
</head>
<body>
<h1>hi!</h1>
<script>

SpecialPowers.wrap(document).userInteractionForTesting();
if (window.location.search == "?messageme") {
  window.opener.postMessage("done", "*");
}
window.close();

</script>
</body>
</html>