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/services/audiopolicy/service/AudioPolicyClientImpl.cpp b/services/audiopolicy/service/AudioPolicyClientImpl.cpp
index 3e090e9..489a9be 100644
--- a/services/audiopolicy/service/AudioPolicyClientImpl.cpp
+++ b/services/audiopolicy/service/AudioPolicyClientImpl.cpp
@@ -213,6 +213,12 @@
     mAudioPolicyService->onAudioPatchListUpdate();
 }
 
+void AudioPolicyService::AudioPolicyClient::onDynamicPolicyMixStateUpdate(
+        String8 regId, int32_t state)
+{
+    mAudioPolicyService->onDynamicPolicyMixStateUpdate(regId, state);
+}
+
 audio_unique_id_t AudioPolicyService::AudioPolicyClient::newAudioUniqueId()
 {
     return AudioSystem::newAudioUniqueId();