AudioPolicyManager: notification of dynamic policy mix activity

Implement non-stream type specific ref counting in output
  descriptors to keep track of mix activity.
Notify audio policy client of mix activity changes.

Bug 20226914

Change-Id: Iec939cb640c58056f88947b611d23b4bb6d8a11b
diff --git a/media/libmedia/AudioPolicy.cpp b/media/libmedia/AudioPolicy.cpp
index c7dafcb..786eb63 100644
--- a/media/libmedia/AudioPolicy.cpp
+++ b/media/libmedia/AudioPolicy.cpp
@@ -68,6 +68,7 @@
     mFormat.format = (audio_format_t)parcel->readInt32();
     mRouteFlags = parcel->readInt32();
     mRegistrationId = parcel->readString8();
+    mFlags = (uint32_t)parcel->readInt32();
     size_t size = (size_t)parcel->readInt32();
     if (size > MAX_CRITERIA_PER_MIX) {
         size = MAX_CRITERIA_PER_MIX;
@@ -89,6 +90,7 @@
     parcel->writeInt32(mFormat.format);
     parcel->writeInt32(mRouteFlags);
     parcel->writeString8(mRegistrationId);
+    parcel->writeInt32(mFlags);
     size_t size = mCriteria.size();
     if (size > MAX_CRITERIA_PER_MIX) {
         size = MAX_CRITERIA_PER_MIX;