<html>
<head>
  <title>3rd party content!</title>
</head>
<body>
<h1>Here the 3rd party content!</h1>
<script>

onmessage = async function(e) {
  let cb = e.data.cb;
  let runnableStr = `(() => {return (${cb});})();`;
  let runnable = eval(runnableStr); // eslint-disable-line no-eval
  let variant = (new URL(location.href)).searchParams.get("variant");
  let win = this;
  if (variant == "initial-aboutblank") {
    let i = win.document.createElement("iframe");
    i.src = "about:blank";
    win.document.body.appendChild(i);
    // override win to make it point to the initial about:blank window
    win = i.contentWindow;
  }

  let result = await runnable.call(this, win, e.data.value);
  parent.postMessage(result, "*");
};

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