The theory is that this will improve build time. Let's try and see what bots say.
Created attachment 356968 [details] proposed patch
Comment on attachment 356968 [details] proposed patch Clearing flags on attachment: 356968 Committed r239054: <https://trac.webkit.org/changeset/239054>
All reviewed patches have been landed. Closing bug.
<rdar://problem/46609968>
This didn't affect build speed at all.