chromium/src/third_party/blink/web_tests/http/tests/xmlhttprequest/resources/close-window-frame.html

<script>
var xhr = new XMLHttpRequest;
xhr.open("GET", location.href + "?");
xhr.send();
window.close();
window.opener.setTimeout("if (window.testRunner) testRunner.notifyDone()", 10);
</script>