The fix for https://bugs.webkit.org/show_bug.cgi?id=198124 broke the tvOS build.
<rdar://problem/51048991>
Committed r245673: <https://trac.webkit.org/changeset/245673>
Committed r245678: <https://trac.webkit.org/changeset/245678>
Committed r245679: <https://trac.webkit.org/changeset/245679>