AudioSystem callback for dynamic policy mix activity

Add method to AudioPolicyServiceClient for dynamic policy mix
 activity notification.
Propagate notification to a dedicated callback.

Bug 20226914

Change-Id: I37928ed38e15ea2b8fed022cccadeca8c4d6c876
diff --git a/media/libmedia/AudioPolicy.cpp b/media/libmedia/AudioPolicy.cpp
index 786eb63..9d07011 100644
--- a/media/libmedia/AudioPolicy.cpp
+++ b/media/libmedia/AudioPolicy.cpp
@@ -68,7 +68,7 @@
     mFormat.format = (audio_format_t)parcel->readInt32();
     mRouteFlags = parcel->readInt32();
     mRegistrationId = parcel->readString8();
-    mFlags = (uint32_t)parcel->readInt32();
+    mCbFlags = (uint32_t)parcel->readInt32();
     size_t size = (size_t)parcel->readInt32();
     if (size > MAX_CRITERIA_PER_MIX) {
         size = MAX_CRITERIA_PER_MIX;
@@ -90,7 +90,7 @@
     parcel->writeInt32(mFormat.format);
     parcel->writeInt32(mRouteFlags);
     parcel->writeString8(mRegistrationId);
-    parcel->writeInt32(mFlags);
+    parcel->writeInt32(mCbFlags);
     size_t size = mCriteria.size();
     if (size > MAX_CRITERIA_PER_MIX) {
         size = MAX_CRITERIA_PER_MIX;