Offer to "merge" subscribers for data usage.

There are some cases where multiple subscriber identities (IMSI)
should be treated as "merged together" from a data usage
perspective.  This is done by extending the template used for
matching purposes to support multiple subscribers.

Then, when we query historical usage or set network policies, we
normalize the matching template to merge to any other identities
that should be included.  When normalizing, the "lowest" identity
is always used for equality and storage purposes, which allows
identities to come and go over time.

This change also fixes data usage recording for multi-SIM devices
by passing along the concrete subscriber identity for each network
interface.  Also correctly create default policies for multi-SIM
devices.  This change also drops setPolicyDataEnable() until it can
be wired up to the right underlying NetworkAgent.  (This means we
still bring up the network, and then rely on iptables rules to block
traffic when over the limit, instead of proactively disabling the

Bug: 18012787
Change-Id: If6acf32009fdfea2b836f5aff8e2f3e5e0248b4a
14 files changed