This checks that writing an X-Frame-Options meta tag to a detached document does not crash.
<script>
if (window.testRunner)
    testRunner.dumpAsText();
</script>
<iframe id=foo></iframe>
<script>
  var fooFrame = document.getElementById('foo');
  var fooDoc = fooFrame.contentWindow.document;
  fooFrame.parentNode.removeChild(fooFrame);

  fooDoc.write('<meta http-equiv="X-Frame-Options" content="deny"/>');
</script>