The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5bab54a253e19d19e446f5084a1b1216f65b97f1

commit 5bab54a253e19d19e446f5084a1b1216f65b97f1
Author: Yi Gu <yigu@chromium.org>
Date: Thu Nov 29 17:08:35 2018

[animation worklet] CurrentTime from DocumentTimeline should be offset by StartTime

Currently upon collecting the inputs for the mutation on main thread, we
don't offset the current time by the start time which is incorrect.

Note:
The layout test animations/animationworklet/worklet-animation-currentTime.html
fails the release build because AnimationClock::currentTime is often
incorrectly ahead of rAF time so that when asking for the current time
in a rAF via getComputedStyle it returns obsolete result. This bug is
tracked by https://crbug.com/785940.

Bug:  905405 
Change-Id: I0b7e293ae942e47b96eb8a7a2a8fefd94be66773
Reviewed-on: https://chromium-review.googlesource.com/c/1343558
Commit-Queue: Yi Gu <yigu@chromium.org>
Reviewed-by: Majid Valipour <majidvp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612238}
[modify] https://crrev.com/5bab54a253e19d19e446f5084a1b1216f65b97f1/third_party/blink/renderer/modules/animationworklet/worklet_animation.cc
[modify] https://crrev.com/5bab54a253e19d19e446f5084a1b1216f65b97f1/third_party/blink/renderer/modules/animationworklet/worklet_animation.h
[modify] https://crrev.com/5bab54a253e19d19e446f5084a1b1216f65b97f1/third_party/blink/renderer/modules/animationworklet/worklet_animation_test.cc
[modify] https://crrev.com/5bab54a253e19d19e446f5084a1b1216f65b97f1/third_party/blink/web_tests/TestExpectations