Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/http/tests/xmlhttprequest/xmlhttprequest-pagehide-sync.html 

<!DOCTYPE html>
<html>
<body>
<p>Test behavior of sync XHR during pagehide</p>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<iframe id="ifr" name="ifr" src="resources/xmlhttprequest-in-pagehide-sync.html"></iframe>
<script>
var t = async_test();

t.step_timeout(() => {
  var iframe = document.getElementById("ifr");
  iframe.src = "about:blank";
}, 1000);

</script>
</body>
</html>