supportedEntryTypes-cross-realm-access.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>Cross-realm access of supportedEntryTypes returns Array of another realm</title>
<link rel="help" href="https://w3c.github.io/performance-timeline/#supportedentrytypes-attribute">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<script>
test(t => {
  const iframe = document.createElement("iframe");
  t.add_cleanup(() => { iframe.remove(); });
  iframe.onload = t.step_func_done(() => {
    const otherWindow = iframe.contentWindow;
    assert_true(otherWindow.PerformanceObserver.supportedEntryTypes instanceof otherWindow.Array);
  });
  document.body.append(iframe);
});
</script>

chromium/third_party/blink/web_tests/external/wpt/performance-timeline/supportedEntryTypes-cross-realm-access.html