Use accessor to read property serial numbers

Hide the implementation of the property structures by using
an accessor.

(cherry picked from commit 14c02f245e56687b765487d25a034d71196d33b6)

Change-Id: Id86ff99d8430fa73bbc745aaa0ff2b7713ca7885
Merge "Use accessor to read property serial numbers"
am 2769ce79: Merge "Use accessor to read property serial numbers"

* commit '2769ce79def80023e454708deec176e3259dc586':
  Use accessor to read property serial numbers
audio policy: apply default device volume

Make sure that we apply default device volume to
active outputs in case no specific volume for selected
device is received afterward.

Bug: 9760269.
Change-Id: I216de40396e1075e77493c97e8b192cd3a31d546
am e92d6238: audio policy: apply default device volume

* commit 'e92d623811f3fd3e7cc5e5dd8bc93c0c0a8fdf50':
  audio policy: apply default device volume
audio policy: apply default device volume

Make sure that we apply default device volume to
active outputs in case no specific volume for selected
device is received afterward.

Bug: 9760269.
Change-Id: I216de40396e1075e77493c97e8b192cd3a31d546
Reconcile with jb-mr2-zeroday-release - do not merge

Change-Id: I44d1b4bc2d06e2ec3d7837693a1880d7e6cf1774