Add ExtendedAudioBufferProvider::framesReleased and onTimestamp

and implement them in SourceAudioBufferProvider using the associated NBAIO_Source,
and in Track using the associated AudioTrackServerProxy.

Change-Id: I60dc4adba63fc1dc452ff16caf347e4a7c8242c2
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index 9622709..db67be6 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -498,6 +498,10 @@
     return status;
 }
 
+// releaseBuffer() is not overridden
+
+// ExtendedAudioBufferProvider interface
+
 // Note that framesReady() takes a mutex on the control block using tryLock().
 // This could result in priority inversion if framesReady() is called by the normal mixer,
 // as the normal mixer thread runs at lower
@@ -510,6 +514,11 @@
     return mAudioTrackServerProxy->framesReady();
 }
 
+size_t AudioFlinger::PlaybackThread::Track::framesReleased() const
+{
+    return mAudioTrackServerProxy->framesReleased();
+}
+
 // Don't call for fast tracks; the framesReady() could result in priority inversion
 bool AudioFlinger::PlaybackThread::Track::isReady() const {
     if (mFillingUpStatus != FS_FILLING || isStopped() || isPausing()) {