chromium/third_party/blink/web_tests/external/wpt/soft-navigation-heuristics/interaction-with-paint-before-back.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="resources/soft-navigation-helper.js"></script>
</head>
<body>
  <main id=main>
    <div>
      <a id=link><img src="/images/lcp-256x256.png" id="img"></a>
      <a id=not_nav><img src="/images/lcp-16x16.png"></a>
    </div>
  </main>
  <script>
    // Push state a couple of times
    history.pushState({}, "", "foobar.html");
    history.pushState({}, "", "anotherOne.html");

    (async () => {
      const link = document.getElementById("link");
      // Trigger a user interaction that doesn't result in a soft navigation, but
      // does paint.
      await (async () => {
        const not_nav = document.getElementById("not_nav");
        let non_soft_nav_click;
        const non_soft_nav_click_promise =
          new Promise(r => { non_soft_nav_click = r; });
        not_nav.addEventListener("click", () => {
          addImageToMain("lcp-133x106.png", "not_soft_nav_image");
          (new PerformanceObserver(non_soft_nav_click)).observe({type: "element"});
        });
        if (test_driver) {
          test_driver.click(not_nav);
        }
        await non_soft_nav_click_promise;
      })();
      const url = URL + "?" + counter;
      link.addEventListener("click", () => {
        // Add an LCP element.
        const img = new Image();
        img.src = '/images/lcp-100x500.png' + "?" + Math.random();
        document.getElementById("main").appendChild(img);
        history.back();
      });
      promise_test(async t => {
        if (test_driver) {
          test_driver.click(link);
        }
        await waitOnSoftNav();
        assert_equals(
            document.softNavigations, 1,
            'Single Soft Navigation detected');
        const [entries, options] = await new Promise(resolve => {
          (new PerformanceObserver((list, obs, options) => resolve(
            [list.getEntries(), options]))).observe(
            {type: 'soft-navigation', buffered: true});
          });

        assert_equals(entries.length, 1,
                      "Performance observer got an entry");
      }, "Ensure that soft navigation entry emitted through a synchronous " +
         "event that modified DOM and committed a same document navigation, " +
         "and that was preceded by a user intreaction that resulted in a " +
         "contentful paint is properly detected.");
    })();
  </script>
</body>
</html>