RTCCertificate-postMessage-iframe.html

<!doctype html>
<script>
window.onmessage = async (event) => {
    let certificate = event.data;
    if (!certificate)
        certificate = await RTCPeerConnection.generateCertificate({ name: 'ECDSA', namedCurve: 'P-256'});
    event.source.postMessage(certificate, "*");
}
</script>

chromium/third_party/blink/web_tests/external/wpt/webrtc/resources/RTCCertificate-postMessage-iframe.html