Bug 3352047 Wrong message when adjusting volume

Add hidden AudioManager.getDevicesForStream and output device codes.

Change-Id: I4d1c1d3b6a077cd117720817d1f733dda557b947
diff --git a/media/libmedia/AudioSystem.cpp b/media/libmedia/AudioSystem.cpp
index 9d9b3c0..2f694ba 100644
--- a/media/libmedia/AudioSystem.cpp
+++ b/media/libmedia/AudioSystem.cpp
@@ -668,6 +668,13 @@
     return aps->getStrategyForStream(stream);
 }
 
+uint32_t AudioSystem::getDevicesForStream(AudioSystem::stream_type stream)
+{
+    const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();
+    if (aps == 0) return 0;
+    return aps->getDevicesForStream(stream);
+}
+
 audio_io_handle_t AudioSystem::getOutputForEffect(effect_descriptor_t *desc)
 {
     const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();