active == shown?
So show virtual keyboard when password field gets focus and dismiss is when it looses focus?

Also, it doesn't seem that password is ever loosing focus. Is that correct? Should that change?   

Sorry, I may have worded this strangely. To be more precise, when the PIN keyboard is shown virtual keyboard should be hidden. When PIN keyboard is hidden virtual keyboard should be shown, if applicable.

I think it also makes sense to hide when the password field loses focus but I don't know if that will be useful (ie, how to tab without VK?)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/57636f80af562a472c4ddd4497f7ec1e60932b93

commit 57636f80af562a472c4ddd4497f7ec1e60932b93
Author: Aga Wronska <agawronska@chromium.org>
Date: Fri Feb 16 17:13:18 2018

Toggle pin keyboard visibility according to virtual keyboard appearance.

Pin keyboard should be only visible when there is no virtul keyboard
displayed.
Observe virtual keyboard state in order to update pin keyboard visibility.

Bug:  799082 
Change-Id: I9ef33faf699dfc78cdd09145f4c2aee43e52afab
Reviewed-on: https://chromium-review.googlesource.com/903414
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537333}
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/lock_contents_view.cc
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/lock_contents_view.h
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/lock_contents_view_unittest.cc
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/login_auth_user_view.cc
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/login_auth_user_view.h
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/login_auth_user_view_unittest.cc
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/login_keyboard_test_base.cc
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/login_keyboard_test_base.h
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/login_test_base.cc
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/login_test_utils.cc
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/login_test_utils.h
[modify] https://crrev.com/57636f80af562a472c4ddd4497f7ec1e60932b93/ash/login/ui/login_user_view_unittest.cc