GitLab

This CL plumbs the IdentityManager through to PSS, via SigninManagerWrapper.
There are no behavioral changes, in particular the IdentityManager isn't
used at all yet. Uses will follow soon (https://crrev.com/c/983914).

This does require a small test change to make the newly-instantiated
IdentityManager happy (without that change, it complains that its view of
the primary account isn't consistent with SigninManager's).

Bug: 825190
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I8b313f5572339a2c1319725fa4012b4a41365e08
Reviewed-on: https://chromium-review.googlesource.com/995414
Commit-Queue: Marc Treib <treib@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548419}