Resync web-platform-tests/interfaces from upstream.
Created attachment 404457 [details] Patch
Created attachment 404462 [details] Patch
Created attachment 404478 [details] Patch
Committed r264478: <https://trac.webkit.org/changeset/264478> All reviewed patches have been landed. Closing bug and clearing flags on attachment 404478 [details].
<rdar://problem/65688724>