AudioTrack: lower Java latency

Add AUDIO_FLAG_LOW_LATENCY to enable Fast track.

Change-Id: Ib1bff635afaa57af7754cb751b57c6afc4c2ab2b
Bug: 21019153
Signed-off-by: Phil Burk <philburk@google.com>
diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index fe4611c..3b2d829 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -811,6 +811,7 @@
     audio_io_handle_t       mOutput;                // returned by AudioSystem::getOutput()
 
     sp<AudioTrackThread>    mAudioTrackThread;
+    bool                    mThreadCanCallJava;
 
     float                   mVolume[2];
     float                   mSendLevel;