[LayoutNG] Give flex algorithm correct main-axis min/max sizes for items

We don't yet compute min-width:auto though.

Bug: 845235
Change-Id: I74fff512b283647cad12406233fc8b68dccfb55e
Reviewed-on: https://chromium-review.googlesource.com/c/1381836
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Commit-Queue: David Grogan <dgrogan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618609}
2 files changed