GitLab

It's currently observer SigninManager but it could instead observe
IdentityManager. This will allow RenderUpdater to eventually use the
identity service.

Bug: 887453
Change-Id: I588bcdaa1e0c5fe02207ad4fabff552193c49766
Reviewed-on: https://chromium-review.googlesource.com/c/1268339
Commit-Queue: Sergio Villar <svillar@igalia.com>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607556}