Bug 1577243 - Backed out changeset cae99e27ccdd, restoring document.timeline and rAF timestamp comparisons r=birtles

Depends on D43788

Differential Revision: https://phabricator.services.mozilla.com/D43789

--HG--
extra : moz-landing-system : lando

dom/animation/test/document-timeline/test_document-timeline.html

@@ -10,10 +10,6 @@
 <script>
 'use strict';
 
-function matchUnconditionalClamping(timestamp) {
-  return parseFloat((Math.floor(timestamp / .02) * .02).toPrecision(8), 10);
-}
-
 test(function() {
   assert_equals(document.timeline, document.timeline,
     'document.timeline returns the same object every time');
@@ -47,7 +43,7 @@ async_test(function(t) {
   // window.performance.now() because currentTime is only updated on a sample
   // so we use requestAnimationFrame instead.
   window.requestAnimationFrame(t.step_func(function(rafTime) {
-    assert_equals(document.timeline.currentTime, matchUnconditionalClamping(rafTime),
+    assert_equals(document.timeline.currentTime, rafTime,
                   'document.timeline.currentTime matches' +
                   ' requestAnimationFrame time');
     t.done();

testing/web-platform/tests/web-animations/timing-model/timelines/document-timelines.html

@@ -9,10 +9,6 @@
 <script>
 'use strict';
 
-function matchUnconditionalClamping(timestamp) {
-  return parseFloat((Math.floor(timestamp / .02) * .02).toPrecision(8), 10);
-}
-
 async_test(t => {
   assert_greater_than_equal(document.timeline.currentTime, 0,
     'The current time is initially is positive or zero');
@@ -32,7 +28,7 @@ async_test(t => {
   // so we use requestAnimationFrame instead.
   window.requestAnimationFrame(rafTime => {
     t.step(() => {
-      assert_equals(document.timeline.currentTime, matchUnconditionalClamping(rafTime),
+      assert_equals(document.timeline.currentTime, rafTime,
                     'The current time matches requestAnimationFrame time');
     });
     t.done();