Add IdentityController to provide user's given/display name.

This interface will be expanded to proxy calls to IdentityAcessor so
that we have more control over what is called and be able to record
metrics.

Bug: 927809
Change-Id: Ifb33c170b17b8ab7e3dbcb89a5fc47288f73814a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1615441
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Reviewed-by: Mustafa Emre Acer <meacer@chromium.org>
Commit-Queue: Bruno Santos <brunoad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661335}
13 files changed