IdentityManager: Add APIs for querying state of refresh tokens

This CL adds APIs to IdentityManager for obtaining the set of all
accounts with refresh tokens and querying whether the primary account
is available with a refresh token.

The design follows that of IdentityManager's caching of the primary
account information:
- IdentityManager initializes its state with the current state of
- IdentityManager updates this state in response to notifications from
  PO2TS that an account's refresh token was updated/removed.

Bug: 806774
Change-Id: Idc4a37a15ced2e7d32f012a50e4e0d1fdb1aecdf
Commit-Queue: Colin Blundell <>
Reviewed-by: Mihai Sardarescu <>
Reviewed-by: Marc Treib <>
Reviewed-by: Sylvain Defresne <>
Cr-Commit-Position: refs/heads/master@{#571451}
4 files changed