so that we can pre-compute some attributes that we need during run construction
Created attachment 413138 [details] Patch
Created attachment 413245 [details] Patch
Created attachment 413279 [details] Patch
Committed r269424: <https://trac.webkit.org/changeset/269424> All reviewed patches have been landed. Closing bug and clearing flags on attachment 413279 [details].
<rdar://problem/71073877>