The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0ae589ea543040a0f0ace7b0f2ac7f79cff0feeb

commit 0ae589ea543040a0f0ace7b0f2ac7f79cff0feeb
Author: Wenzhao Zang <wzang@chromium.org>
Date: Thu Nov 30 19:20:49 2017

cros: Add dev channel version info to lock debug view

A follow-up of adding the info to views-based lock (CL 786635)

Bug:  789755 
Change-Id: If869eba2e770667fbee607e6e2ff2093d2cf26a8
Reviewed-on: https://chromium-review.googlesource.com/798852
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520637}
[modify] https://crrev.com/0ae589ea543040a0f0ace7b0f2ac7f79cff0feeb/ash/login/ui/lock_debug_view.cc
[modify] https://crrev.com/0ae589ea543040a0f0ace7b0f2ac7f79cff0feeb/ash/login/ui/lock_debug_view.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b84a9cb6b15a6d4163f67ba91f12e4c271e61095

commit b84a9cb6b15a6d4163f67ba91f12e4c271e61095
Author: Wenzhao Zang <wzang@chromium.org>
Date: Sat Dec 02 02:09:52 2017

cros: Fix DCHECK failure of dev channel info button

1) A follow-up to CL 798852, which causes a DCHECK failure.

2) Changed 'Toggle' to 'Add'. In production there's no way to toggle
   the channel info back to empty.

3) Iteratively adds information. Disable the button after all the info
   has been updated to simulate the real scenario.

Bug:  789755 
Change-Id: Id62a52fc822a7f41ad4cd35955b3ce7e9d1f058d
Reviewed-on: https://chromium-review.googlesource.com/803749
Commit-Queue: Wenzhao (Colin) Zang <wzang@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521180}
[modify] https://crrev.com/b84a9cb6b15a6d4163f67ba91f12e4c271e61095/ash/login/ui/lock_debug_view.cc
[modify] https://crrev.com/b84a9cb6b15a6d4163f67ba91f12e4c271e61095/ash/login/ui/lock_debug_view.h