Use the absolute magnitude instead of the bar level as the level of the input signal

content/renderer/media/media_stream_audio_level_calculator.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_
 #define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_
 
 #include "base/threading/thread_checker.h"
 
 namespace content {
 
 // This class is used by the WebRtcLocalAudioTrack to calculate the  level of
 // the audio signal. And the audio level will be eventually used by the volume
 // animation UI.
 // The algorithm used by this class is the same as how it is done in
 // third_party/webrtc/voice_engine/level_indicator.cc.
 class MediaStreamAudioLevelCalculator {
  public:
   MediaStreamAudioLevelCalculator();
   ~MediaStreamAudioLevelCalculator();
 
   // Calculates the signal level of the audio data.
-  // Returns the level of bars that the volume animation UI uses for
-  // presenting the energy level of the audio data.
+  // Returns the absolute value of the amplitude of the signal.
   int Calculate(const int16* audio_data, int number_of_channels,
                 int number_of_frames);
 
  private:
   // Used to DCHECK that the constructor and Calculate() are always called on
   // the same audio thread. Note that the destructor will be called on a
   // different thread, which can be either the main render thread or a new
   // audio thread where WebRtcLocalAudioTrack::OnSetFormat() is called.
   base::ThreadChecker thread_checker_;
 
   int counter_;
   int max_amplitude_;
   int level_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_LEVEL_CALCULATOR_H_