Make the RegisteredSErvices Cache not allow the registered service for a

type to change without first uninstalling the previous service for that
type, unless the newly installed service is in the system image.

Notify the listener when a service is added or removed.

Make the AccountManagerService remove the accounts for an authenticator
when the registered authenticator changes from one uid to another.

Make the AbstractSyncableContentProvider force a sync when the database is first created.