[LayoutNG] Fix rtl flip for out-of-flow positioned objects in lineboxes.

This changes the rtl flip calculation. Before it was using the wrong
line_offset, and the static position of abs-pos were getting shifted
with the text-alignment (which shouldn't be occuring).

This using the appropriate line-offset, and corrects the rtl flip
calculation.

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I93a45e196682ee1a940fe81b4c43f67e19fe6bb3
Bug: 636993
Reviewed-on: https://chromium-review.googlesource.com/1153219
Reviewed-by: Koji Ishii <kojii@chromium.org>
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578742}
2 files changed