GitLab

Merges the temporary type LINE_BREAK_MULTILINE to LINE_BREAK and introduces
new type FIELD_BREAK for edge selection. As LineSelectionModel returns
EdgeSelectionModel for a single line text, there is no behavioral change.
Adds some tests for FIELD_BREAK.

Change-Id: I7636852f13e61a6e0b8a70ca59d4f925c1c68ce3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1626845
Commit-Queue: Michael Wasserman <msw@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664402}