chromium/third_party/blink/web_tests/external/wpt/html/cross-origin-embedder-policy/no-secure-context.html

<!doctype html>
<meta charset=utf-8>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/get-host-info.sub.js"></script>
<div id=log></div>
<script>
async_test(t => {
  const frame = document.body.appendChild(document.createElement("iframe"));
  t.add_cleanup(() => frame.remove());
  frame.src = get_host_info().HTTP_NOTSAMESITE_ORIGIN + new URL("resources/iframe.html", location).pathname;
  window.onmessage = t.step_func_done(({ data }) => {
    assert_equals(data, "success");
  });
  frame.onload = t.step_func(() => {
    frame.contentWindow.postMessage("parent.postMessage('success', '*');", "*");
  });
}, "COEP requires a secure context");
</script>