GitLab

Allow lacros to get, set, and be notified for changes in ash prefs.

Bug: 1161413
Bug: 1163288
Change-Id: Ie086018acf4d7fa8378a968415f76792543a2f39
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2607983
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Reviewed-by: Erik Chen <erikchen@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841295}