no-sandboxed-automatic-features.html

<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/utils.js"></script>

<iframe sandbox srcdoc="<input autofocus>"></iframe>

<script>
'use strict';

promise_test(async () => {
  await waitForLoad(window);
  await waitUntilStableAutofocusState();
  assert_not_equals(document.activeElement, document.querySelector('iframe'));
}, 'If the sandboxed automatic features browsing context flag is set, ' +
    'autofocus in the browsing context should not be handled.');
</script>

chromium/third_party/blink/web_tests/external/wpt/html/interaction/focus/the-autofocus-attribute/no-sandboxed-automatic-features.html