GitLab

Add strings and screenshots for the upcoming switch button on
the login/lock screen.

Bug: 1075994
Change-Id: Ic5aa9b083dc2251edda7ad7a634bf93f17f1981b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2346264
Commit-Queue: Renato Silva <rrsilva@google.com>
Auto-Submit: Renato Silva <rrsilva@google.com>
Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796357}