diff --git a/services/audioflinger/PlaybackTracks.h b/services/audioflinger/PlaybackTracks.h
index 6a138bb..33983d7 100644
--- a/services/audioflinger/PlaybackTracks.h
+++ b/services/audioflinger/PlaybackTracks.h
@@ -310,6 +310,7 @@
         binder::Status unmute(/*out*/ bool *ret) override;
     private:
         Track* const mTrack;
+        bool setMute(bool muted);
     };
     sp<AudioVibrationController> mAudioVibrationController;
     sp<os::ExternalVibration>    mExternalVibration;