Remove usage of OAuth2TokenServiceDelegate

A lot of the usage can be replaced by simple calls to the token service
itself. This is better, because the delegate is not meant to be exposed.

Change-Id: I8e4813308c890e0bccad03779f429fa902066178
Reviewed-on: https://chromium-review.googlesource.com/995893
Reviewed-by: Colin Blundell <blundell@chromium.org>
Commit-Queue: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549538}
5 files changed