Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/external/wpt/partitioned-popins/resources/partitioned-popins.close.html 

<!doctype html>
<meta charset="utf-8">
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<script>
(async function() {
  test_driver.set_test_context(window.opener);
  window.close();
})();
</script>