Modified the signature of the abstract volume methods so
it is clear at the subclass level whether the volume
command is for a mute or a volume control.
Changed the implementations in the subclasses
accordingly.
Removed appOps handling inside SoundPool and made it
inherit from PlayerBase.
Moved handling of the camera sound restriction from
SoundPool to PlayerBase.
Added support in SoundPool native implementation for
muting, as each player has its own volume.
Test: play a long file with SoundPool and enter DnD mode
Bug: 30955183
Bug: 28249605
Change-Id: I0fcd7480f9a455c06aa4f7092486f5c65bc9d7db
8e48c6939b