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@@ -0,0 +1,88 @@
+<!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>