helper_smoothscroll_spam_interleaved.html

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<!DOCTYPE HTML>

<html>

<head>

  <meta charset="utf-8">

  <meta name="viewport" content="width=device-width; initial-scale=1.0">

  <title>Test for scenario in bug 1228407 with two scrollframes</title>

  <script type="application/javascript" src="apz_test_native_event_utils.js"></script>

  <script type="application/javascript" src="apz_test_utils.js"></script>

  <script src="/tests/SimpleTest/paint_listener.js"></script>

  <script type="application/javascript">

async function test() {

  let utils = SpecialPowers.getDOMWindowUtils(window);

  utils.advanceTimeAndRefresh(0);

  // Basically the same setup as in helper_smoothscroll_spam.html, but

  // with two scrollframes that get scrolled in an interleaved manner.

  // The original fix for bug 1228407 left this scenario unhandled, with

  // bug 1231177 tracking the problem. This test exercises the scenario.

  let s1 = document.getElementById('s1');

  let s2 = document.getElementById('s2');

  for (let i = 0; i < 100; i++) {

    s1.scrollBy({top:60, behavior: "smooth"});

    s2.scrollBy({top:60, behavior: "smooth"});

    await promiseOnlyApzControllerFlushed();

    utils.advanceTimeAndRefresh(16);

  utils.restoreNormalRefresh();

  await promiseOnlyApzControllerFlushed();

  let s1pos = s1.scrollTop;

  let s2pos = s2.scrollTop;

  ok(s1pos > 60, `s1 scrolled ${s1pos}px, should be more than 60`);

  ok(s2pos > 60, `s2 scrolled ${s2pos}px, should be more than 60`);

waitUntilApzStable().then(test).then(subtestDone, subtestFailed);

  </script>

  <style>

    .scrollable {

      overflow: scroll;

      height: 300px;

    .content {

      height: 1000px;

      background-image: linear-gradient(green, blue);

  </style>

</head>

<body>

 <div id="s1" class="scrollable"><div class="content"></div></div>

 <div id="s2" class="scrollable"><div class="content"></div></div>

</body>

</html>