New module for the adaptive level controlling functionality in the audio processing module

webrtc/modules/audio_processing/include/audio_processing.h

Index: webrtc/modules/audio_processing/include/audio_processing.h
diff --git a/webrtc/modules/audio_processing/include/audio_processing.h b/webrtc/modules/audio_processing/include/audio_processing.h
index 2f8e48f82dab70b9ee57da104d9a0a4dad67de6c..d25c2525b30d485cb5d0d6dde04c04449e5157dc 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -92,6 +92,14 @@ struct RefinedAdaptiveFilter {
   bool enabled;
 };
 
+// Enables the adaptive level controller.
+struct LevelControl {
+  LevelControl() : enabled(false) {}
+  explicit LevelControl(bool enabled) : enabled(enabled) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kLevelControl;
+  bool enabled;
+};
+
 // Enables delay-agnostic echo cancellation. This feature relies on internally
 // estimated delays between the process and reverse streams, thus not relying
 // on reported system delays. This configuration only applies to