chromium/src/third_party/blink/web_tests/http/tests/security/cors-rfc1918/resources/post-addressspace-from-serviceworker.html

<script src="/resources/testharness.js"></script>
<script src="/serviceworker/resources/test-helpers.js"></script>
<script>

async function receiveMessageFromServiceWorker(worker) {
    return new Promise((resolve) => {
        // Use a dedicated message channel to avoid unexpected messages.
        const channel = new MessageChannel();
        channel.port1.onmessage = e => resolve(e.data);
        worker.postMessage("Don't care", [channel.port2]);
    });
}

promise_test(async t => {
    const script = "/security/cors-rfc1918/resources/post-addressspace-to-owner-serviceworker.js";
    const scope = "/security/cors-rfc1918/resources/post-addressspace-from-serviceworker.html";

    const params = new URLSearchParams(location.search);
    const workerType = params.get("workerType");
    const options = { type: workerType };

    const registration = await service_worker_unregister_and_register(
        t, script, scope, options);
    t.add_cleanup(_ => registration.unregister());

    await wait_for_state(t, registration.installing, "activated");

    const message = await receiveMessageFromServiceWorker(registration.active);
    window.parent.postMessage(message, "*");
}, "Address space tests for service worker");

</script>