Reland of added functionality for specifying the initial signal level to use for the gain estimation

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 1d8e043cce410adbb1b07e970b41bf75f08a4395..1030f7952e57650be28994bf62995948b8610f5a 100644
--- a/webrtc/modules/audio_processing/level_controller/level_controller.h
+++ b/webrtc/modules/audio_processing/level_controller/level_controller.h
@@ -38,6 +38,10 @@ class LevelController {
   void Process(AudioBuffer* audio);
   float GetLastGain() { return last_gain_; }
 
+  // TODO(peah): This method is a temporary solution as the the aim is to
+  // instead apply the config inside the constructor. Therefore this is likely
+  // to change.
+  void ApplyConfig(const AudioProcessing::Config::LevelController& config);
   // Validates a config.
   static bool Validate(const AudioProcessing::Config::LevelController& config);
   // Dumps a config to a string.
@@ -80,6 +84,8 @@ class LevelController {
   float dc_level_[2];
   float dc_forgetting_factor_;
   float last_gain_;
+  bool gain_jumpstart_ = false;
+  AudioProcessing::Config::LevelController config_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(LevelController);
 };