Revert "Web-animation: Remove some uses of PlayStateUpdateScope."

This reverts commit af74d157.

Reason for revert: pref regression in queuing durations

Original change's description:
> Web-animation: Remove some uses of PlayStateUpdateScope.
> 
> PlayStateUpdateScope is problematic for handling timing of finished
> promises in addition to not conforming with the algorithm outlined in
> the web-animations spec. This patch removes several uses of
> PlayStateUpdateScope and refines handling of pending flags.
> 
> Bug: 960944
> Change-Id: I093a3aa86084adfbe128a5aedd36206d67dd12c8
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1851927
> Commit-Queue: Kevin Ellis <kevers@chromium.org>
> Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#705966}

TBR=kevers@chromium.org,majidvp@chromium.org,smcgruer@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 960944
Change-Id: Ib16d862d5834f837717e64bb86277860e50ec11a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1866624Reviewed-by: Kevin Ellis <kevers@chromium.org>
Reviewed-by: Majid Valipour <majidvp@chromium.org>
Commit-Queue: Kevin Ellis <kevers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707821}

third_party/blink/renderer/core/animation/animation.h

@@ -144,12 +144,11 @@ class CORE_EXPORT Animation : public EventTargetWithInlineData,
   ScriptPromise ready(ScriptState*);
 
   bool Paused() const {
-    return CalculateAnimationPlayState() == kPaused && !is_paused_for_testing_;
+    return GetPlayState() == kPaused && !is_paused_for_testing_;
   }
 
   bool Playing() const override {
-    return CalculateAnimationPlayState() == kRunning && !Limited() &&
-           !is_paused_for_testing_;
+    return GetPlayState() == kRunning && !Limited() && !is_paused_for_testing_;
   }
 
   // Indicates if the animation is out of sync with the compositor. A change to
@@ -337,9 +336,6 @@ class CORE_EXPORT Animation : public EventTargetWithInlineData,
   void ScheduleAsyncFinish();
   void AsyncFinishMicrotask();
   void CommitFinishNotification();
-  void CommitPendingPause(double ready_time);
-  void CommitPendingPlay(double ready_time);
-  void ApplyUpdates(double ready_time);
 
   // Tracking the state of animations in dev tools.
   void NotifyProbe();

third_party/blink/renderer/core/animation/animation_test.cc

@@ -169,8 +169,6 @@ class AnimationAnimationTestNoCompositing : public RenderingTest {
   }
 
   bool SimulateFrame(double time_ms) {
-    animation->CommitAllUpdatesForTesting();
-
     last_frame_time = time_ms;
     const auto* paint_artifact_compositor =
         GetDocument().GetFrame()->View()->GetPaintArtifactCompositor();
@@ -441,8 +439,7 @@ TEST_F(AnimationAnimationTestNoCompositing, StartTimeWithZeroPlaybackRate) {
   animation->setPlaybackRate(0);
   EXPECT_EQ("running", animation->playState());
   SimulateAwaitReady();
-  EXPECT_EQ("running", animation->playState());
-  EXPECT_EQ(0, animation->startTime());
+  EXPECT_FALSE(animation->startTime());
 
   SimulateFrame(10000);
   EXPECT_EQ("running", animation->playState());

third_party/blink/web_tests/animations/web-animations/animation-state-changes-negative-playback-rate.html

@@ -82,7 +82,7 @@ test(function() {
 
 test(function() {
   var animation = finishedAnimation();
-  assert_times_equal(animation.startTime, document.timeline.currentTime - (animation.playbackRate * animation.currentTime));
+  assert_equals(animation.startTime, document.timeline.currentTime - (animation.playbackRate * animation.currentTime));
   assert_equals(animation.currentTime, 0);
   assert_false(animation.pending);
   assert_equals(animation.playState, 'finished');
@@ -118,7 +118,7 @@ test(function() {
 test(function() {
   var animation = idleAnimation();
   animation.finish();
-  assert_times_equal(animation.startTime, document.timeline.currentTime - (animation.playbackRate * animation.currentTime));
+  assert_equals(animation.startTime, document.timeline.currentTime - (animation.playbackRate * animation.currentTime));
   assert_equals(animation.currentTime, 0);
   assert_false(animation.pending);
   assert_equals(animation.playState, 'finished');
@@ -221,7 +221,7 @@ test(function() {
   animation.play();
   assert_equals(animation.startTime, startTime);
   assert_equals(animation.currentTime, currentTime);
-  assert_false(animation.pending);
+  assert_true(animation.pending);
   assert_equals(animation.playState, 'running');
 }, "Calling play() on a running animation");
 

third_party/blink/web_tests/animations/web-animations/animation-state-changes-positive-playback-rate.html

@@ -212,7 +212,7 @@ test(function(t) {
   animation.play();
   assert_equals(animation.startTime, startTime);
   assert_equals(animation.currentTime, currentTime);
-  assert_false(animation.pending);
+  assert_true(animation.pending);
   assert_equals(animation.playState, 'running');
 }, "Setting play() on a running animation");