Content sometimes missing in nested scrollers with border-radius
Created attachment 402698 [details] Patch
<rdar://problem/64460373>
Created attachment 402716 [details] Patch
Created attachment 402809 [details] Patch
Created attachment 402879 [details] Patch
Committed r263578: <https://trac.webkit.org/changeset/263578> All reviewed patches have been landed. Closing bug and clearing flags on attachment 402879 [details].