chromium/content/test/data/nested_page_with_subresources.html

<!DOCTYPE html>
<body>
<script>
  var i = document.createElement("iframe");
  i.src = location.protocol + "//not-" + location.hostname + (location.port ? (":" + location.port) : "") + "/page_with_subresources.html";
  document.body.appendChild(i);
</script>
</body>