Surface the IntelligibilityEnhancer on MediaConstraints

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 142 matching lines @@
               SphericalPointf target_direction)
       : enabled(enabled),
         array_geometry(array_geometry),
         target_direction(target_direction) {}
   static const ConfigOptionID identifier = ConfigOptionID::kBeamforming;
   const bool enabled;
   const std::vector<Point> array_geometry;
   const SphericalPointf target_direction;
 };
 
-// Use to enable intelligibility enhancer in audio processing. Must be provided
-// though the constructor. It will have no impact if used with
-// AudioProcessing::SetExtraOptions().
+// Use to enable intelligibility enhancer in audio processing.
 //
 // Note: If enabled and the reverse stream has more than one output channel,
 // the reverse stream will become an upmixed mono signal.
 struct Intelligibility {
   Intelligibility() : enabled(false) {}
   explicit Intelligibility(bool enabled) : enabled(enabled) {}
   static const ConfigOptionID identifier = ConfigOptionID::kIntelligibility;
   bool enabled;
 };
 
@@ skipping 804 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_