Created attachment 188464 [details]
Bug 109880 was done in preparation for this.
Created attachment 188619 [details]
Comment on attachment 188619 [details]
Now that I've seen the code, I think a const_cast of |this| in computeIntrinsicLogicalWidths would be better. It feels weird to me that placeItemsOnGrid is const.
Committed r143043: <http://trac.webkit.org/changeset/143043>