This makes it more future-proof and maintainable, not exposing the internal bitpacking state. The implementation is unchanged (the policy is still just an int we pass around). Also starts to introduce VmPolicy, for things which are process-wide, not per-thread. As an initial user, make SQLite's Cursor finalization leak warnings use StrictMode. Change-Id: Idedfba4e965716f5089a52036421460b1f383725