Expand the use of existing cache. This will make porting code in VisibleUnit.cpp easier.
Created attachment 414340 [details] patch
Created attachment 414360 [details] patch
Committed r269916: <https://trac.webkit.org/changeset/269916> All reviewed patches have been landed. Closing bug and clearing flags on attachment 414360 [details].
<rdar://problem/71498032>