Migrate PeopleHandler to the IdentityManager

Use the APIs from IdentityManager and PrimaryAccountsMutator to migrate
calls previously depending on SigninManager and ProfileOAuth2TokenService.

Bug: 898810, 920236, 920237, 921445
Change-Id: I22b046bae82e2539d165d95573c27d47affa6a06
Reviewed-on: https://chromium-review.googlesource.com/c/1298994
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623185}
2 files changed