By the time we start computing height and width, DisplayBox should already have the computed values.
Created attachment 340374 [details] Patch
Comment on attachment 340374 [details] Patch Clearing flags on attachment: 340374 Committed r231780: <https://trac.webkit.org/changeset/231780>
All reviewed patches have been landed. Closing bug.
<rdar://problem/40251739>