Users outside system_server now explicitly communicate their
lifecycle, which keeps a strong-reference chain to any fully loaded
NetworkStatsCollection histories.
Bug: 6236498
Change-Id: I8e22739b6e89a626b676967a736d7117fd000778
Add networkId field to NetworkIdentity to identify Wi-Fi networks by
SSID. Add support for policies without usage cycles.
Only apply mobile policies when SIM state is ready, which is cleaner
than just checking for airplane mode. Also avoids creating no-op
default policies when subscriberId is null.
Bug: 3001465, 3291052
Change-Id: I1f8aaa49a5db306df022c402ea7f3f5d4bc0cfc7