The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1cf1dd71ae420fcd553a24d18d828a17c4cad1b6

commit 1cf1dd71ae420fcd553a24d18d828a17c4cad1b6
Author: Steven Bennetts <stevenjb@chromium.org>
Date: Fri Jan 04 20:14:22 2019

Remove SystemSaltGetter from Ash

SystemSaltGetter::Get() is only used in src/chrome, and src/login/auth
(which is only used by src/chrome), so remove initialization and
shutdown from AshService and AshTestHelper. This allows us to remove
the //chromeos/cryptohome dependency from //ash entirely.

Bug:  918922 
Change-Id: I08d63d6b4ecd39ff8acac013253ff3c58d431e08
Reviewed-on: https://chromium-review.googlesource.com/c/1396320
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620044}
[modify] https://crrev.com/1cf1dd71ae420fcd553a24d18d828a17c4cad1b6/ash/ash_service.cc
[modify] https://crrev.com/1cf1dd71ae420fcd553a24d18d828a17c4cad1b6/ash/test/ash_test_helper.cc
[modify] https://crrev.com/1cf1dd71ae420fcd553a24d18d828a17c4cad1b6/chrome/browser/chromeos/extensions/quick_unlock_private/quick_unlock_private_api_unittest.cc