The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b796bdf0f66ae56caabc85f8b3b2e663bfd95d4f

commit b796bdf0f66ae56caabc85f8b3b2e663bfd95d4f
Author: Jacob Dufault <jdufault@google.com>
Date: Thu Jun 28 23:15:48 2018

cros: Center user list for 6+ users in views login/lock.

Bug:  854453 
Change-Id: I7e1e187ce37a90036a4335ddd333f56b35bf1ac1
Reviewed-on: https://chromium-review.googlesource.com/1117709
Reviewed-by: Aga Wronska <agawronska@chromium.org>
Commit-Queue: Jacob Dufault <jdufault@chromium.org>
Cr-Commit-Position: refs/heads/master@{#571319}
[modify] https://crrev.com/b796bdf0f66ae56caabc85f8b3b2e663bfd95d4f/ash/login/ui/scrollable_users_list_view.cc
[modify] https://crrev.com/b796bdf0f66ae56caabc85f8b3b2e663bfd95d4f/ash/login/ui/scrollable_users_list_view.h

Still need a CL that hides the gradient when there is no scrollbar.

https://chromium-review.googlesource.com/c/chromium/src/+/1142234 hides the gradient when there is no scrollbar

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a125aaea45e932c652e5c2efe92c3258883efd1b

commit a125aaea45e932c652e5c2efe92c3258883efd1b
Author: Jacob Dufault <jdufault@google.com>
Date: Wed Aug 08 21:58:45 2018

cros: Hide gradient on login user list when no scrolling is needed.

Bug:  854453 
Change-Id: Id5cb3abcc0d41238c9a8c760faa6b10235a3781b
Reviewed-on: https://chromium-review.googlesource.com/1142234
Commit-Queue: Jacob Dufault <jdufault@chromium.org>
Reviewed-by: Aga Wronska <agawronska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581700}
[modify] https://crrev.com/a125aaea45e932c652e5c2efe92c3258883efd1b/ash/login/ui/scrollable_users_list_view.cc
[modify] https://crrev.com/a125aaea45e932c652e5c2efe92c3258883efd1b/ash/login/ui/scrollable_users_list_view.h