as opposed to having new renderers appended.
Created attachment 465140 [details] Patch
Created attachment 465141 [details] Patch
Created attachment 465142 [details] Patch
Created attachment 465149 [details] Patch
Created attachment 465168 [details] [fast-cq]Patch
Committed 260837@main (3c7d37eae4c7): <https://commits.webkit.org/260837@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 465168 [details].
<rdar://problem/105926623>