layout/style/test/test_transitions_replacement_with_setKeyframes.html

<!doctype html>
<html>
<!--
https://bugzilla.mozilla.org/show_bug.cgi?id=1292001
-->
<head>
  <meta charset=utf-8>
  <title>Test for bug 1292001</title>
  <script src="/tests/SimpleTest/SimpleTest.js"></script>
  <script src="/tests/SimpleTest/paint_listener.js"></script>
  <script src="animation_utils.js"></script>
  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css">
  <style>
    #target {
      height: 100px;
      width: 100px;
      background: green;
      transition: transform 100s linear;
    }
  </style>
</head>
<body>
<div id="target"></div>
<script>
'use strict';

SimpleTest.waitForExplicitFinish();

const OMTAPrefKey = 'layers.offmainthreadcomposition.async-animations';
const omtaEnabled =
  SpecialPowers.DOMWindowUtils.layerManagerRemote &&
  SpecialPowers.getBoolPref(OMTAPrefKey);

window.addEventListener('load', async function() {
  if (!omtaEnabled) {
    ok(true, 'Skipping the test since OMTA is disabled');
    SimpleTest.finish();
    return;
  }

  const div = document.getElementById('target');

  // Start first transition
  div.style.transform = 'translateX(300px)';
  const firstTransition = div.getAnimations()[0];

  // But then change its keyframes to something completely different.
  firstTransition.effect.setKeyframes({ 'opacity': ['0', '1'] });

  // Wait for the transition to start running on the main thread and
  // compositor.
  await firstTransition.ready;
  await waitForPaints();
  await new Promise(resolve => requestAnimationFrame(resolve));

  // Start second transition
  div.style.transform = 'translateX(600px)';
  const secondTransition = div.getAnimations()[0];

  const previousKeyframeValue = secondTransition.effect.getKeyframes()[0]
    .transform;

  // Tie up main thread for 300ms. In the meantime, the first transition
  // will continue running on the compositor. If we don't update the start
  // point of the second transition, it will appear to jump when it starts.
  const startTime = performance.now();
  while (performance.now() - startTime < 300);

  // Ensure that our paint process has been done.
  //
  // (See explanation in test_transitions_replacement_on_busy_frame.html for
  // why we don't use requestAnimationFrame here.)
  await waitForPaints();

  // Now check that the keyframes are NOT updated.
  is(
    secondTransition.effect.getKeyframes()[0].transform,
    previousKeyframeValue,
    'Keyframe value of transition is NOT updated since the moment when ' +
      'it was generated'
  );

  SimpleTest.finish();
});

</script>
</body>
</html>