Breakout from http://crrev.com/2469903002 and  http://crbug.com/658874 . We landed http://crrev.com/2507893002 as an interim step to fix common cases. Cases we suspect are broken involve permutations of composited row/section with and without composited cell.

Next step would be to look at creating add'l failing edge test cases as discussed on first change above, and exploring less complex fixes.