chromium/third_party/blink/web_tests/external/wpt/soft-navigation-heuristics/softnav-after-lcp-paint-larger-than-viewport.tentative.html

<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<script src="/soft-navigation-heuristics/resources/soft-navigation-helper.js"></script>
<link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
</head>
<body>
  <main id=main>
    <div>
      <a id=link><img id="initial_image1" src="/images/lcp-256x256.png?1" style="width: 90vw; height: 90vh">
        <div id=extra></div>
      </a>
    </div>
  </main>
  <script>
  (async () => {
    const link = document.getElementById("link");

    // Inject a second image that takes a large part of the viewport.
    await new Promise(resolve => {
      requestAnimationFrame(() => requestAnimationFrame(() => {
        document.getElementById("extra").innerHTML = `
          <div style="position: absolute; bottom: 0; right: 0">
            <img id="initial_image2" src="/images/lcp-256x256.png?2" style="width: 90vw;height: 90vh">
          </div>`;
        resolve();
      }));
    });
    // Wait until the second image is rendered.
    await new Promise(resolve => {
      requestAnimationFrame(() => requestAnimationFrame(() => {
        resolve();
      }));
    });
    testSoftNavigation({
      addContent: async () => {
        // Remove the initial image, so that the text would be painted on screen.
        document.getElementById("initial_image1").remove();
        document.getElementById("initial_image2").remove();
        let lcp_element_painted;
        const lcp_element_paint_promise = new Promise((r) => { lcp_element_painted = r; });
        // Add an LCP element, but have it be small enough to not trigger the
        // Soft Navigation heuristics.
        const p = addTextParagraphToMain(
          "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod",
          /*element_timing=*/"lcp");
        (new PerformanceObserver(list => {
          // Once the first element is fully painted:
          lcp_element_painted();
        })).observe({type: "element", buffered: true});
        await lcp_element_paint_promise;
        // Add a smaller element that gets us over that threshold.
        addTextParagraphToMain("dolore magna aliqua.");
      },
      link: link,
      test: "Test that an image LCP followed by a smaller soft navigation LCP"
        + " properly queues an LCP entry, even when the soft navigation is"
        + " detected after the LCP, even when initial paints significantly"
        + " exceed the viewport dimensions."});
  })();
  </script>
</body>
</html>