Passing an IdentityTestEnvironment:: IdentityManager instance to AndroidManagementClient (in place of OAuth2TokenService instance) breaks arc_android_management_checker.cc line 56

We should also take care of fixing arc_android_management_checker.cc

Yes, your analysis is spot-on. Thank you! Updated the bug summary.

To give the context:

- It looks like I never captured the need to convert AndroidManagementClient in a bug (likely because it doesn't include profile_oauth2_token_service.h).
- The only remaining usage of PO2TS in arc_android_management_checker.cc is to pass it to AndroidManagementClient (Antonio had earlier ported all the other usage).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/97836873a9a766395933c9541a327b93c8be0b83

commit 97836873a9a766395933c9541a327b93c8be0b83
Author: Abhijeet Kandalkar <abhijeet@igalia.com>
Date: Fri Jan 18 11:25:40 2019

Port android_management related classes to IdentityManager

This CL ports android_management_client to IdentityManager and
android_management_client_unittest to IdentityTestEnvironment by passing
an IdentityManager instance to AndroidManagementClient in place of PO2TS
instance.

This CL also fixes arc_android_management_checker away from talking to
ProfileOAuth2TokenService in favor of talking to IdentityManager.

Bug:  906021 
Change-Id: I0554f9a608ac75c555372bc4552d1960bbbbabd3
Reviewed-on: https://chromium-review.googlesource.com/c/1405109
Commit-Queue: Abhijeet Kandalkar <abhijeet@igalia.com>
Reviewed-by: Sergey Poromov <poromov@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624074}
[modify] https://crrev.com/97836873a9a766395933c9541a327b93c8be0b83/chrome/browser/chromeos/arc/policy/arc_android_management_checker.cc
[modify] https://crrev.com/97836873a9a766395933c9541a327b93c8be0b83/chrome/browser/chromeos/policy/android_management_client.cc
[modify] https://crrev.com/97836873a9a766395933c9541a327b93c8be0b83/chrome/browser/chromeos/policy/android_management_client.h
[modify] https://crrev.com/97836873a9a766395933c9541a327b93c8be0b83/chrome/browser/chromeos/policy/android_management_client_unittest.cc