Refactor RMSLevel and give it new functionality

webrtc/modules/audio_processing/level_estimator_impl.h

Index: webrtc/modules/audio_processing/level_estimator_impl.h
diff --git a/webrtc/modules/audio_processing/level_estimator_impl.h b/webrtc/modules/audio_processing/level_estimator_impl.h
index df43c9be0d069070e275d3c312652ab448afd364..11dbdbe5875f4ae0f1327350615fbf7c87e825ea 100644
--- a/webrtc/modules/audio_processing/level_estimator_impl.h
+++ b/webrtc/modules/audio_processing/level_estimator_impl.h
@@ -20,7 +20,7 @@
 namespace webrtc {
 
 class AudioBuffer;
-class RMSLevel;
+class RmsLevel;
 
 class LevelEstimatorImpl : public LevelEstimator {
  public:
@@ -39,7 +39,7 @@ class LevelEstimatorImpl : public LevelEstimator {
  private:
   rtc::CriticalSection* const crit_ = nullptr;
   bool enabled_ GUARDED_BY(crit_) = false;
-  std::unique_ptr<RMSLevel> rms_ GUARDED_BY(crit_);
+  std::unique_ptr<RmsLevel> rms_ GUARDED_BY(crit_);
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(LevelEstimatorImpl);
 };
 }  // namespace webrtc