In order to be able to resolve the current time of animation with threaded animation resolution, we will need to make the timeline time origin available to the UI Process through the `RemoteLayerTreeTransaction`.
<rdar://problem/118882053>
Pull request: https://github.com/WebKit/WebKit/pull/20999
Committed 271234@main (96332f0a2170): <https://commits.webkit.org/271234@main> Reviewed commits have been landed. Closing PR #20999 and removing active labels.