GitLab

Add the annotations button and bar to the new toolbar. Hook up the
button so that entering/exiting annotation mode works.

Bug: 1105732
Change-Id: I87f1067b474c552295c66c0946ce98a813083b4a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2298999Reviewed-by: dpapad <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#788779}