GitLab

Adds tests for docked magnifier, dictation, switch access, and some more
for select-to-speak.

Adds coverage for lines which change checked state of the
HoverHighlightViews, and also checks checked state as well as
the bool for tests. Total line coverage increase from 64% to 96%
in tray_accessibility.cc.

Some clean-up to reduce common lines in helper functions within
the test.

Bug: 1067399
Relnotes: N/A
Change-Id: I05ae85ac043c9fa71e0813a1f0948d990d82afbf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2135022
Commit-Queue: Katie Dektar <katie@chromium.org>
Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757068}