largest-contentful-paint/redirects-tao-star.html

<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8" />
<title>This test validates LargestContentfulPaint information for cross-origin redirect chain images.</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/largest-contentful-paint-helpers.js"></script>
<script src=/common/get-host-info.sub.js></script>
</head>
<body>
<script>
async_test(t => {
    assert_precondition(window.LargestContentfulPaint, "LargestContentfulPaint is not implemented");
    let destUrl = get_host_info().HTTP_REMOTE_ORIGIN
            + '/resource-timing/resources/multi_redirect.py?';
    destUrl += 'page_origin=' +  get_host_info().HTTP_ORIGIN;
    destUrl += '&cross_origin=' + get_host_info().HTTP_REMOTE_ORIGIN;
    destUrl += '&final_resource=' + '/element-timing/resources/circle-tao.svg';
    destUrl += '&timing_allow=1';
    destUrl += '&tao_steps=';

    const image = document.createElement('img');
    image.src = destUrl + '0';
    image.setAttribute('id', 'id');
    document.body.appendChild(image);

    let numObserved = 0;
    let beforeLoad = performance.now();

    new PerformanceObserver(t.step_func(entries => {
        assert_equals(entries.getEntries().length, 1);
        const entry = entries.getEntries()[0];
        const options = numObserved === 3 ? [] : ['renderTimeIs0'];
        checkImage(entry, destUrl + numObserved, 'id', 200 * 200, beforeLoad, options);
        numObserved++;
        if (numObserved === 4)
            t.done();
        else {
            // Change the image to trigger a new LCP entry.
            const img = document.getElementById('id');
            image.src = destUrl + numObserved;
            beforeLoad = performance.now();
        }
    })).observe({type: 'largest-contentful-paint'});
}, 'Cross-origin image without TAO should not have its renderTime set, with full TAO it should.');
</script>
</body>
</html>