chromium/third_party/blink/web_tests/test_runner/notify_done_and_close.html

<script>
  // Note: Closing the main window affects the web_tests logic when switching
  // from one test to the next one. To reproduce a crash, it was necessary to
  // have multiple tests enqueued.
  if (testRunner) {
    testRunner.waitUntilDone();
    setTimeout(() => {
      testRunner.notifyDone();
      close();
    }, 50)
  }
</script>