If 'margin-left', or 'margin-right' are computed as 'auto', their used value is '0'
Created attachment 342024 [details] Patch
Comment on attachment 342024 [details] Patch Clearing flags on attachment: 342024 Committed r232540: <https://trac.webkit.org/changeset/232540>
All reviewed patches have been landed. Closing bug.
<rdar://problem/40852253>