In the layout tests we're using gridAutoFlowRow and gridAutoFlowColumn, which implies that the auto-placement algorithm is using "sparse" mode (as this is the default mode).
Changing it to gridAutoFlowRowSparse and gridAutoFlowColumnSparse to make it more explicit.
This is being managed in https://codereview.chromium.org/401473003/
Created attachment 235069 [details]
Comment on attachment 235069 [details]
Clearing flags on attachment: 235069
Committed r171293: <http://trac.webkit.org/changeset/171293>
All reviewed patches have been landed. Closing bug.