The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/de19f338aa8fc7e4e99d5b07a1b154923b6f0217

commit de19f338aa8fc7e4e99d5b07a1b154923b6f0217
Author: Findit <findit-for-me@appspot.gserviceaccount.com>
Date: Fri Jan 18 03:18:31 2019

Revert "[animation-worklet] Enable wpt tests to run with threaded compostiting"

This reverts commit 85c4dcec46ee24b011320781e22180e57513816e.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 623836 as the
culprit for flakes in the build cycles as shown on:
https://findit-for-me.appspot.com/waterfall/flake/flake-culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vODVjNGRjZWM0NmVlMjRiMDExMzIwNzgxZTIyMTgwZTU3NTEzODE2ZQw

Sample Failed Build: https://ci.chromium.org/buildbot/chromium.mac/Mac10.11%20Tests/33028

Sample Failed Step: webkit_layout_tests on (none) GPU on Mac on Mac-10.11.6

Sample Flaky Test: virtual/threaded/external/wpt/animation-worklet/current-time.https.html

Original change's description:
> [animation-worklet] Enable wpt tests to run with threaded compostiting
> 
> 
> Bug: 915352
> Change-Id: Iead91d55465c0277dfaa9588d413e654a5d1a57a
> Reviewed-on: https://chromium-review.googlesource.com/c/1418076
> Commit-Queue: Majid Valipour <majidvp@chromium.org>
> Reviewed-by: Xida Chen <xidachen@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#623836}

Change-Id: I2eb82ad256d0ec8f370b8d160b4a150933196623
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 915352,  923225 
Reviewed-on: https://chromium-review.googlesource.com/c/1420303
Cr-Commit-Position: refs/heads/master@{#623987}
[modify] https://crrev.com/de19f338aa8fc7e4e99d5b07a1b154923b6f0217/third_party/blink/web_tests/VirtualTestSuites
[delete] https://crrev.com/a5e641f741c98c4ee25ebb8f9105398f7cad2d81/third_party/blink/web_tests/virtual/threaded/external/wpt/animation-worklet/README.txt

Findit identified the culprit r623836 as introducing flaky test(s)
summarized in https://findit-for-me.appspot.com/waterfall/flake/flake-culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vODVjNGRjZWM0NmVlMjRiMDExMzIwNzgxZTIyMTgwZTU3NTEzODE2ZQw

Please revert the culprit or disable the test(s) asap. If you are the owner,
please fix!

If the culprit above is wrong, please file a bug using this link:
https://bugs.chromium.org/p/chromium/issues/entry?status=Unconfirmed&labels=Pri-1,Test-Findit-Wrong&components=Tools%3ETest%3EFindit%3EFlakiness&summary=%5BFindit%5D%20Flake%20Analyzer%20-%20Wrong%20culprit%20r623836&comment=Link%20to%20Culprit%3A%20https://findit-for-me.appspot.com/waterfall/flake/flake-culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vODVjNGRjZWM0NmVlMjRiMDExMzIwNzgxZTIyMTgwZTU3NTEzODE2ZQw

Automatically posted by the findit-for-me app (https://goo.gl/Ot9f7N).

The culprit has been reverted. Marking as fixed.