Added functionality for specifying the initial signal level to use for the gain estimation in the l…

webrtc/modules/audio_processing/level_controller/level_controller.h

Index: webrtc/modules/audio_processing/level_controller/level_controller.h
diff --git a/webrtc/modules/audio_processing/level_controller/level_controller.h b/webrtc/modules/audio_processing/level_controller/level_controller.h
index 3d203f908d53b9f564cc9f6ef2aa9a68b3e19f1e..1d7f174562f92a44a919b0916aef1ae447b494c4 100644
--- a/webrtc/modules/audio_processing/level_controller/level_controller.h
+++ b/webrtc/modules/audio_processing/level_controller/level_controller.h
@@ -38,6 +38,11 @@ class LevelController {
   void Process(AudioBuffer* audio);
   float GetLastGain() { return last_gain_; }
 
+  // Sets the initial peak level to use inside the level controller in order
+  // to compute the signal gain. The unit for the peak level is dBFS and
+  // the allowed range is [-100, 0].
+  void SetInitialLevel(float level);
+
  private:
   class Metrics {
    public:
@@ -71,6 +76,7 @@ class LevelController {
   float dc_level_[2];
   float dc_forgetting_factor_;
   float last_gain_;
+  bool gain_jumpstart_ = false;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(LevelController);
 };