RemoteScrollingCoordinator::scheduleTreeStateCommit() can be called in the middle of a compositing update. Instead of just handling that scrolling tree commit in the current update (which is what would happen if it called into Page::scheduleRenderingUpdate()), it triggers another update after the current one, because it just calls the WebKit2-level drawingArea()->triggerRenderingUpdate().
<rdar://problem/99353273>
Pull request: https://github.com/WebKit/WebKit/pull/14281
Committed 264503@main (750b577cdf3f): <https://commits.webkit.org/264503@main> Reviewed commits have been landed. Closing PR #14281 and removing active labels.
Re-opened since this is blocked by bug 257738