AudioPolicy: callback for recording configuration change

Each AudioSession tracks start / end of recording, and sends
  a callback to AudioSystem.
AudioSystem tracks a single recording callback tracking
  input source and audio session number.

Change-Id: Ic065751d9ba013e03f2a6ad8dde02542e5465ec0
diff --git a/media/libmedia/AudioSystem.cpp b/media/libmedia/AudioSystem.cpp
index 9d645f0..46622ea 100644
--- a/media/libmedia/AudioSystem.cpp
+++ b/media/libmedia/AudioSystem.cpp
@@ -37,6 +37,7 @@
 sp<AudioSystem::AudioFlingerClient> AudioSystem::gAudioFlingerClient;
 audio_error_callback AudioSystem::gAudioErrorCallback = NULL;
 dynamic_policy_callback AudioSystem::gDynPolicyCallback = NULL;
+record_config_callback  AudioSystem::gRecordConfigCallback = NULL;
 
 
 // establish binder interface to AudioFlinger service
@@ -652,6 +653,12 @@
     gDynPolicyCallback = cb;
 }
 
+/*static*/ void AudioSystem::setRecordConfigCallback(record_config_callback cb)
+{
+    Mutex::Autolock _l(gLock);
+    gRecordConfigCallback = cb;
+}
+
 // client singleton for AudioPolicyService binder interface
 // protected by gLockAPS
 sp<IAudioPolicyService> AudioSystem::gAudioPolicyService;
@@ -1223,6 +1230,19 @@
     }
 }
 
+void AudioSystem::AudioPolicyServiceClient::onRecordingConfigurationUpdate(
+        int event, audio_session_t session, audio_source_t source) {
+    record_config_callback cb = NULL;
+    {
+        Mutex::Autolock _l(AudioSystem::gLock);
+        cb = gRecordConfigCallback;
+    }
+
+    if (cb != NULL) {
+        cb(event, session, source);
+    }
+}
+
 void AudioSystem::AudioPolicyServiceClient::binderDied(const wp<IBinder>& who __unused)
 {
     {