chromium/third_party/blink/web_tests/external/wpt/largest-contentful-paint/non-tao-image-load-before-fcp-render-after.tentative.html

<!DOCTYPE HTML>
<meta charset=utf-8>
<title>Non-Tao Image Load Before FCP and Render After FCP.
</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>

<body>
  <script>
    promise_test(async t => {
      const non_tao_image_url = get_host_info().OTHER_ORIGIN + '/images/blue.png';

      img = await loadImage(non_tao_image_url, true);

      // Add text so that FCP is set and image rendering time would be larger than FCP.
      add_text('Add to set FCP');

      // wait for 1 animation frame so that FCP is set.
      await raf();

      // Pass empty string to select the LCP entry corresponding to the text as LCP.url is
      // empty for text elements.
      lcp = await getLCPStartTime('');

      img.style.opacity = 1;

      lcp = await getLCPStartTime('blue.png');

      fcp = getFCPStartTime();

      checkLCPEntryForNonTaoImages({ 'lcp': lcp, 'fcp': fcp });
    }, 'Non-Tao Image Load Before FCP and Render After FCP.')
  </script>
</body>