GitLab

Makes XPositionForOffset and CharacterIndexForPosition support
return results inside a ligature glyph (while still not breaking ZWJs)
by using a character-based TextBreakIterator inside glyphs.

Reland of 1e3235b3

Bug: 473476
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I80348a10044edc89f0e85789c71dc17a56f6393d
Reviewed-on: https://chromium-review.googlesource.com/1140275
Commit-Queue: Fernando Serboncini <fserb@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Reviewed-by: Fernando Serboncini <fserb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575822}