[LayoutNG] Fix margins for orthogonal atomic inlines

When computing margins for orthogonal atomic inlines, the old
code was using the writing-mode of the atomic inline to
determine whether to flip line or not.

This patch fixes to use the constraint space's writing-mode.

For other computation than flipped-lines,
ComputeMarginsForVisualContainer already uses the writing-
mode of the constraint space.

Bug: 636993
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I85d12a29cf5e845d3fef00b9832c68d106e80dca
Reviewed-on: https://chromium-review.googlesource.com/1179519
Commit-Queue: Koji Ishii <kojii@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584028}
2 files changed