Add API for auto-complete ranking improvement.

- primary account (3510087)
- per-method ranking (4371572)

Primary account enables to ContactsProvider to prioritize
email addresses associated with the account.

Per-method ranking enables ContactsProvider to get feedback
from applications about usage per method instead of that per
person.

Both should be available for unbundled applications.

Bug: 3510087
Bug: 4371572
Change-Id: Icb01415317a7dbb6538804181b06bd973af6205c