This function abstracts https://encoding.spec.whatwg.org/#utf-8-decode so I think it's better to place to TextResourceDecoder
Created attachment 401847 [details] Patch
Committed r263022: <https://trac.webkit.org/changeset/263022> All reviewed patches have been landed. Closing bug and clearing flags on attachment 401847 [details].
<rdar://problem/64354388>