LoudnessEnhancer audio effect implementation

Implementation based on DRC effect, controlled by a
 target gain.
 The target gain is used to amplify the signal at
 the input of the DRC, and to compute the knee
 of the DRC.

Bug 8413913

Change-Id: I386d64793a9fa3f7218e053d6f0a99f6836c02bd
diff --git a/media/libeffects/data/audio_effects.conf b/media/libeffects/data/audio_effects.conf
index 69a3c53..c3c4b67 100644
--- a/media/libeffects/data/audio_effects.conf
+++ b/media/libeffects/data/audio_effects.conf
@@ -35,6 +35,9 @@
   downmix {
     path /system/lib/soundfx/libdownmix.so
   }
+  loudness_enhancer {
+    path /system/lib/soundfx/libldnhncr.so
+  }
 }
 
 # Default pre-processing library. Add to audio_effect.conf "libraries" section if
@@ -122,6 +125,10 @@
     library downmix
     uuid 93f04452-e4fe-41cc-91f9-e475b6d1d69f
   }
+  loudness_enhancer {
+    library loudness_enhancer
+    uuid fa415329-2034-4bea-b5dc-5b381c8d1e2c
+  }
 }
 
 # Default pre-processing effects. Add to audio_effect.conf "effects" section if