The LayoutNG behavior looks correct with the current ruby architecture.
The light-blue box is a child of <rt>, and it should not overlap with
the ruby base text.

Bug: 1069817
Change-Id: Id6eef5444a5c77a4e55c3451c52cb12d2b0d842d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2249214Reviewed-by: Koji Ishii <kojii@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779754}