Integrate Intelligibility with APM

webrtc/modules/audio_processing/include/audio_processing.h

Index: webrtc/modules/audio_processing/include/audio_processing.h
diff --git a/webrtc/modules/audio_processing/include/audio_processing.h b/webrtc/modules/audio_processing/include/audio_processing.h
index 6fa1c96c0771c14d141836dc0c88bf69ec9f5aea..52b62d9db903ba62962ff22e51383e7ea13a3930 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -122,6 +122,14 @@ struct AudioProcessing48kHzSupport {
   bool enabled;
 };
 
+// Use to enable intelligibility enhancer in audio processing. It can be set
+// in the constructor or using AudioProcessing::SetExtraOptions().
+struct Intelligibility {
+  Intelligibility() : enabled(false) {}
+  explicit Intelligibility(bool enabled) : enabled(enabled) {}
+  bool enabled;
+};
+
 static const int kAudioProcMaxNativeSampleRateHz = 32000;
 
 // The Audio Processing Module (APM) provides a collection of voice processing
@@ -303,8 +311,8 @@ class AudioProcessing {
                             float* const* dest) = 0;
 
   // Analyzes a 10 ms |frame| of the reverse direction audio stream. The frame
-  // will not be modified. On the client-side, this is the far-end (or to be
-  // rendered) audio.
+  // will not be modified, unless intelligibility is enabled. On the client-
+  // side, this is the far-end (or to be rendered) audio.
   //
   // It is only necessary to provide this if echo processing is enabled, as the
   // reverse stream forms the echo reference signal. It is recommended, but not
@@ -321,7 +329,7 @@ class AudioProcessing {
 
   // Accepts deinterleaved float audio with the range [-1, 1]. Each element
   // of |data| points to a channel buffer, arranged according to |layout|.
-  virtual int AnalyzeReverseStream(const float* const* data,
+  virtual int AnalyzeReverseStream(float* const* data,
                                    int samples_per_channel,
                                    int sample_rate_hz,
                                    ChannelLayout layout) = 0;