An AudioMixingRule is a collection of AudioAttributes and match/exclude
rules.
An AudioMix is defined by its AudioMixingRule, AudioFormat and
routing flag.
An AudioPolicyConfig is a collection of AudioMix and is
parcellable.
An AudioPolicy has an AudioPolicyConfig, and
can be registered/unregistered through AudioManager.
bug 16009464
Change-Id: I01bf95d014967f48ba823648ea897779da099e5d