largest-contentful-paint/non-tao-image-subsequent-lcp-candidate.tentative.html

<!DOCTYPE HTML>
<meta charset=utf-8>
<title>Non-Tao Image Subsequent LCP candidates.
</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 => {
      let small_image_path = '/images/lcp-100x50.png';
      let big_image_path = '/images/lcp-256x256.png';
      let non_tao_scheme = get_host_info().OTHER_ORIGIN;

      // Load non-tao image with 0 opacity so it won't trigger an LCP entry.
      big_image = await loadImage(non_tao_scheme + big_image_path, true);

      // Load a smaller non-tao image with 0 opacity.
      small_image = await loadImage(non_tao_scheme + small_image_path, true);

      // Add text so that FCP is set.
      add_text('text');

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

      // The url of text LCP element is empty.
      lcp = await getLCPStartTime('');

      // Rendered loaded image after FCP.
      small_image.style.opacity = 1;
      lcp = await getLCPStartTime(small_image_path);

      fcp = getFCPStartTime();

      checkLCPEntryForNonTaoImages({ 'lcp': lcp, 'fcp': fcp });

      // This is to verify subsequent LCP candidates also have the start time set correctly.
      big_image.style.opacity = 1;

      lcp = await getLCPStartTime(big_image_path);

      checkLCPEntryForNonTaoImages({ 'lcp': lcp, 'fcp': fcp });

    }, 'Non-Tao Image Subsequent LCP candidates.')
  </script>
</body>