[macOS UI-side compositing] Mouse handling can trigger a crash before we have a scrolling tree root
Created attachment 364026 [details] Patch
Comment on attachment 364026 [details] Patch Antti rubber-stamped this.
Comment on attachment 364026 [details] Patch Clearing flags on attachment: 364026 Committed r242645: <https://trac.webkit.org/changeset/242645>
All reviewed patches have been landed. Closing bug.
<rdar://problem/48717344>