Summary: While adding tests for CSSEdge I found that when setting both horizontal/vertical/all + left/right then left/right were not correctly overriding the others. This is now fixed and validated through added tests
Reviewed By: lucasr
Differential Revision: D3791106
fbshipit-source-id: 3e0c943f94218848a1fbf36e5ae48dbc720ea923
