This is to support off-main-thread AX TextMarker APIs.
<rdar://problem/118914925>
Created attachment 468798 [details] Patch
Comment on attachment 468798 [details] Patch Seems like we could wrap a lot more code in the conditionals
Created attachment 468799 [details] Patch
Created attachment 468806 [details] Patch
Created attachment 468814 [details] Patch
Committed 271328@main (aec51b1ace31): <https://commits.webkit.org/271328@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 468814 [details].