Bug 3352047 Wrong message when adjusting volume

Add hidden AudioManager.getDevicesForStream and output device codes.

Change-Id: I4d1c1d3b6a077cd117720817d1f733dda557b947
diff --git a/include/media/AudioSystem.h b/include/media/AudioSystem.h
index 03f8944..2dc4beb 100644
--- a/include/media/AudioSystem.h
+++ b/include/media/AudioSystem.h
@@ -392,6 +392,7 @@
     static status_t getStreamVolumeIndex(stream_type stream, int *index);
 
     static uint32_t getStrategyForStream(stream_type stream);
+    static uint32_t getDevicesForStream(stream_type stream);
 
     static audio_io_handle_t getOutputForEffect(effect_descriptor_t *desc);
     static status_t registerEffect(effect_descriptor_t *desc,