Add parameter for set visualizer latency

b/6522728

Change-Id: If30ba44d44e54fd0a514ce5357ac438f8ae3ec5b
diff --git a/audio_effects/include/audio_effects/effect_visualizer.h b/audio_effects/include/audio_effects/effect_visualizer.h
index 45bac5a..7c74f35 100644
--- a/audio_effects/include/audio_effects/effect_visualizer.h
+++ b/audio_effects/include/audio_effects/effect_visualizer.h
@@ -41,6 +41,7 @@
 {
     VISUALIZER_PARAM_CAPTURE_SIZE, // Sets the number PCM samples in the capture.
     VISUALIZER_PARAM_SCALING_MODE, // Sets the way the captured data is scaled
+    VISUALIZER_PARAM_LATENCY,      // Informs the visualizer about the downstream latency
 } t_visualizer_params;
 
 /* commands */