beforeunload-sticky-destination.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>Beforeunload must be gated behind sticky activation: destination page</title>

<p>If you reached this page without clicking through a confirmation dialog, then the test has passed!

<script>
if (window.opener) {
  window.opener.postMessage('navigated successfully');
} else if (window.parent) {
  window.parent.postMessage('navigated successfully');
}
</script>

chromium/third_party/blink/web_tests/external/wpt/html/browsers/browsing-the-web/unloading-documents/support/beforeunload-sticky-destination.html