css/cssom-view/resize-event-on-initial-layout.html

<!DOCTYPE html>
<meta charset=utf-8>
<meta name="viewport" content="width=device-width">
<link rel="help" href="https://drafts.csswg.org/cssom-view/#run-the-resize-steps"/>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script>
promise_test(async t => {
  let gotResizeEvent = false;

  on_event(window, 'resize', () => gotResizeEvent = true);

  await new Promise(resolve  => requestAnimationFrame(resolve));
  await new Promise(resolve  => requestAnimationFrame(resolve));

  assert_false(gotResizeEvent, 'resize event should not be fired');
}, 'resize events are not fired on the initial layout');
</script>