navigate-child-to-about-blank-in-grandchild-unload.html

<html>
<body>
<a id="a" href="about:blank"></a>
<iframe id="iframe"></iframe>
<script>
if (window.testRunner) {
  testRunner.dumpAsText();
  testRunner.waitUntilDone();
}

iframe.contentWindow.onunload = () => {
  a.click();
  if (window.testRunner)
    testRunner.notifyDone();
};
window.location = 'javascript:"PASS did not crash."';
</script>
</body>
</html>

chromium/third_party/blink/web_tests/fast/loader/resources/navigate-child-to-about-blank-in-grandchild-unload.html