[LayoutNG] Treat CSS-generated hyphen fragments as anonymous text

CSS-generated hyphen fragments are not eligible for resolving caret
positions. Therefore, this patch sets them as anonymous text.

This patch fixes a crasher with bidi caret affinity enabled.

Bug: 894651
Change-Id: Ica88604de97dd415fbb92f29e094c0347887a7c3
Reviewed-on: https://chromium-review.googlesource.com/c/1406136
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621806}
2 files changed