they return a FormattingGeometry object
Created attachment 429459 [details] Patch
Created attachment 429460 [details] Patch
Created attachment 429545 [details] Patch
Committed r277957 (238084@main): <https://commits.webkit.org/238084@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 429545 [details].
<rdar://problem/78409658>