Convert IntelligibilityEnhancer to multi-threaded mode

webrtc/modules/audio_processing/include/audio_processing.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 911 matching lines @@
   virtual Level level() const = 0;
 
   // Returns the internally computed prior speech probability of current frame
   // averaged over output channels. This is not supported in fixed point, for
   // which |kUnsupportedFunctionError| is returned.
   virtual float speech_probability() const = 0;
 
   // Returns the noise estimate per frequency bin averaged over all channels.
   virtual std::vector<float> NoiseEstimate() = 0;
 
+  // Returns the number of bins of the noise estimate.
+  virtual size_t num_noise_bins() const = 0;

[peah-webrtc, 2016/03/08 07:02:38]

I don't think we should put methods in here unless absolutely necessary. This
API is part of the public APM API, which means that anything that is put here
may be used outside of APM. We are trying to remove the submodule public API as
it is very hard to maintain.

This method could instead be put into NoiseSuppressionImpl as it is only used
within APM, right? In that way it will not be publicly visible outside of APM.

[hlundin-webrtc, 2016/03/08 10:28:48]

Acknowledged.

[aluebs-webrtc, 2016/03/08 10:53:00]

Good point. Done.

+
  protected:
   virtual ~NoiseSuppression() {}
 };
 
 // The voice activity detection (VAD) component analyzes the stream to
 // determine if voice is present. A facility is also provided to pass in an
 // external VAD decision.
 //
 // In addition to |stream_has_voice()| the VAD decision is provided through the
 // |AudioFrame| passed to |ProcessStream()|. The |vad_activity_| member will be
@@ skipping 36 matching lines @@
   // This does not impact the size of frames passed to |ProcessStream()|.
   virtual int set_frame_size_ms(int size) = 0;
   virtual int frame_size_ms() const = 0;
 
  protected:
   virtual ~VoiceDetection() {}
 };
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_INCLUDE_AUDIO_PROCESSING_H_