Those guards were added in r213472. https://trac.webkit.org/changeset/213472/webkit Removing them is not causing any test failures presently.
Created attachment 324519 [details] Patch
Comment on attachment 324519 [details] Patch r=me
Comment on attachment 324519 [details] Patch Clearing flags on attachment: 324519 Committed r223831: <https://trac.webkit.org/changeset/223831>
All reviewed patches have been landed. Closing bug.
<rdar://problem/35568702>