AudioTrack obtain/release buffer comments

Change-Id: I0eb178d1ab4eea7f72f4c55852c19b216ca55f5f
diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp
index 1d5fc95..3c3eadc 100644
--- a/media/libmedia/AudioTrack.cpp
+++ b/media/libmedia/AudioTrack.cpp
@@ -1340,6 +1340,7 @@
 
 void AudioTrack::releaseBuffer(Buffer* audioBuffer)
 {
+    // FIXME add error checking on mode, by adding an internal version
     if (mTransfer == TRANSFER_SHARED) {
         return;
     }