[layoutng] Use the correct layout algorithm to compute min/max sizes

This also required adding a check in NGBlockNode::ComputeMinMaxSize
for whether we are inside of PerformLayout -- on Mac, we can
compute preferred sizes outside of layout; however, we can't do
actual layout in that case, so we have to fallback to legacy
min/max size in this case (c.f. RenderViewImpl::CheckPreferredSize())

Bug: 635619
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I0caf0c6c79264074ccaf9f45b83a420950dab715
Reviewed-on: https://chromium-review.googlesource.com/1131562
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575545}
5 files changed