These are no longer necessary for ToT.
<rdar://problem/91571030>
Created attachment 457260 [details] Patch
Created attachment 457285 [details] Patch
Created attachment 457291 [details] Patch
Comment on attachment 457291 [details] Patch r=me. So much dead code removed!
Created attachment 457641 [details] Patch for landing
Committed r292882 (249652@main): <https://commits.webkit.org/249652@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 457641 [details].