The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/44243c3dbc42d90b31f410ba8a778105dc11da6b

commit 44243c3dbc42d90b31f410ba8a778105dc11da6b
Author: rsorokin <rsorokin@chromium.org>
Date: Fri Feb 17 15:30:10 2017

Don't let creating Google accounts on the Active Directory devices.

BUG= 676297 
TEST=ExistingUserControllerActiveDirectoryTest.*
TBR=grt@chromium.org

Review-Url: https://codereview.chromium.org/2701753004
Cr-Commit-Position: refs/heads/master@{#451308}

[modify] https://crrev.com/44243c3dbc42d90b31f410ba8a778105dc11da6b/chrome/app/chromeos_strings.grdp
[modify] https://crrev.com/44243c3dbc42d90b31f410ba8a778105dc11da6b/chrome/browser/chromeos/login/existing_user_controller.cc
[modify] https://crrev.com/44243c3dbc42d90b31f410ba8a778105dc11da6b/chrome/browser/chromeos/login/existing_user_controller_browsertest.cc
[modify] https://crrev.com/44243c3dbc42d90b31f410ba8a778105dc11da6b/chrome/browser/chromeos/login/ui/webui_login_display.cc
[modify] https://crrev.com/44243c3dbc42d90b31f410ba8a778105dc11da6b/chrome/browser/chromeos/policy/device_policy_cros_browser_test.cc
[modify] https://crrev.com/44243c3dbc42d90b31f410ba8a778105dc11da6b/chrome/browser/chromeos/policy/device_policy_cros_browser_test.h
[modify] https://crrev.com/44243c3dbc42d90b31f410ba8a778105dc11da6b/chrome/browser/chromeos/settings/install_attributes.cc
[modify] https://crrev.com/44243c3dbc42d90b31f410ba8a778105dc11da6b/chrome/browser/chromeos/settings/install_attributes.h
[modify] https://crrev.com/44243c3dbc42d90b31f410ba8a778105dc11da6b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc

Can someone provide more information on this on what should be tested to verify this.Is it just trying to sign in with @google.com with add person? 

Yes. With any google account (@gmail.com, @google.com...)
Device should be enrolled into Active Directory domain.