Track pid for each session

so they can be properly freed.

Change-Id: I6f389035bc29e74e7c367c1c6d0252b180f666b3
diff --git a/media/libmedia/AudioSystem.cpp b/media/libmedia/AudioSystem.cpp
index 87f4b4c..140fb66 100644
--- a/media/libmedia/AudioSystem.cpp
+++ b/media/libmedia/AudioSystem.cpp
@@ -435,19 +435,19 @@
     return af->newAudioSessionId();
 }
 
-void AudioSystem::acquireAudioSessionId(int audioSession)
+void AudioSystem::acquireAudioSessionId(int audioSession, pid_t pid)
 {
     const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
     if (af != 0) {
-        af->acquireAudioSessionId(audioSession);
+        af->acquireAudioSessionId(audioSession, pid);
     }
 }
 
-void AudioSystem::releaseAudioSessionId(int audioSession)
+void AudioSystem::releaseAudioSessionId(int audioSession, pid_t pid)
 {
     const sp<IAudioFlinger>& af = AudioSystem::get_audio_flinger();
     if (af != 0) {
-        af->releaseAudioSessionId(audioSession);
+        af->releaseAudioSessionId(audioSession, pid);
     }
 }