navigation-api/scroll-behavior/after-transition-reload.html

<!doctype html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<div id="buffer" style="height: 1000px; width: 1000px;"></div>
<div id="frag"></div>
<div style="height: 1000px; width: 1000px;"></div>
<script>
promise_test(async t => {
  // Wait for after the load event so that the navigation doesn't get converted
  // into a replace navigation.
  await new Promise(resolve => window.onload = () => t.step_timeout(resolve, 0));
  assert_equals(window.scrollY, 0);
  await navigation.navigate("#frag").finished;
  // Scroll down 10px from #frag
  window.scrollBy(0, 10);
  let scrollY_frag_plus_10 = window.scrollY;

  let intercept_resolve;
  let navigate_event;
  navigation.onnavigate = e => {
    navigate_event = e;
    e.intercept({ handler: () => new Promise(r => intercept_resolve = r),
                  scroll: "after-transition" });
  };
  let reload_promises = navigation.reload();
  await reload_promises.committed;

  // removing the <div id="buffer"> should scroll up 1000px.
  assert_equals(window.scrollY, scrollY_frag_plus_10);
  buffer.remove();
  let scrollY_after_buffer_remove = window.scrollY;
  assert_equals(scrollY_after_buffer_remove, scrollY_frag_plus_10 - 1000);

  // Finishing should scroll to #frag, which is 10px up from the current location
  intercept_resolve();
  await reload_promises.finished;
  assert_equals(window.scrollY, scrollY_after_buffer_remove - 10);
}, "scroll: after-transition should work on a reload navigation");
</script>
</body>