Bug 1631850 [wpt PR 23145] - Initialize start time of scroll animatio…

…ns to zero., a=testonly

Automatic update from web-platform-tests
Initialize start time of scroll animations to zero.

Implemented web-animations-1 spec changes introduces in [1].

- Update play and pause procedures to initialize start time of scroll
  animations to zero.
- Updated calculate play state procedure to return "running" state for
  animations that has start time resolved.
- Added/modified tests reflecting spec changes.

[1] w3c/csswg-drafts#4842

Bug: 1070637
Change-Id: Ic83995899b2f3f8d8f985f84b8a2b438bbad7c35
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2150687
Commit-Queue: Olga Gerchikov <gerchikomicrosoft.com>
Reviewed-by: Majid Valipour <majidvpchromium.org>
Reviewed-by: Kevin Ellis <keverschromium.org>
Cr-Commit-Position: refs/heads/master{#761974}

--

wpt-commits: 46978682c5d3e2ff08468be05564307a9a75e06b
wpt-pr: 23145

UltraBlame original commit: e563517d3d930c71fde7bffe58aa64a68dce2d15

testing/web-platform/tests/scroll-animations/element-based-offset.html

@@ -486,6 +486,30 @@
 }
 )
 ;
+/
+/
+Wait
+for
+new
+animation
+frame
+which
+allows
+the
+timeline
+to
+compute
+new
+/
+/
+current
+time
+.
+await
+waitForNextFrame
+(
+)
+;
 const
 animation
 =
@@ -571,6 +595,21 @@
 (
 )
 ;
+assert_true
+(
+animation
+.
+pending
+"
+Animation
+is
+in
+pending
+state
+.
+"
+)
+;
 /
 /
 Verify
@@ -594,9 +633,7 @@
 current
 time
 is
-a
-hold
-time
+zero
 in
 Pending
 state
@@ -609,13 +646,13 @@
 animation
 .
 startTime
-null
+0
 "
 The
 start
 time
 is
-null
+zero
 in
 Pending
 state