Add new variance update option and unittests for intelligibility

webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.h

Index: webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.h
diff --git a/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.h b/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.h
index 8125707f120981c40817152a80bcbea43f2e3006..846c38dd18ed476f5debcce7d44c2e8bf07dabbb 100644
--- a/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.h
+++ b/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.h
@@ -83,6 +83,8 @@ class IntelligibilityEnhancer {
     AudioSource source_;
   };
   friend class TransformCallback;
+  FRIEND_TEST_ALL_PREFIXES(IntelligibilityEnhancerTest, TestErbCreation);
+  FRIEND_TEST_ALL_PREFIXES(IntelligibilityEnhancerTest, TestSolveForGains);
 
   // Sends streams to ProcessClearBlock or ProcessNoiseBlock based on source.
   void DispatchAudio(AudioSource source,
@@ -97,6 +99,12 @@ class IntelligibilityEnhancer {
   // Computes and sets modified gains.
   void AnalyzeClearBlock(float power_target);
 
+  // Bisection search for optimal |lambda|.
+  void SolveForLambda(float power_target, float power_bot, float power_top);
+
+  // Transforms freq gains to ERB gains.
+  void UpdateErbGains();
+
   // Updates variance calculation for noise input with |in_block|.
   void ProcessNoiseBlock(const std::complex<float>* in_block,
                          std::complex<float>* out_block);
@@ -118,16 +126,6 @@ class IntelligibilityEnhancer {
   // Returns dot product of vectors specified by size |length| arrays |a|,|b|.
   static float DotProduct(const float* a, const float* b, int length);
 
-  static const int kErbResolution;
-  static const int kWindowSizeMs;
-  static const int kChunkSizeMs;
-  static const int kAnalyzeRate;   // Default for |analysis_rate_|.
-  static const int kVarianceRate;  // Default for |variance_rate_|.
-  static const float kClipFreq;
-  static const float kConfigRho;  // Default production and interpretation SNR.
-  static const float kKbdAlpha;
-  static const float kGainChangeLimit;
-
   const int freqs_;         // Num frequencies in frequency domain.
   const int window_size_;   // Window size in samples; also the block size.
   const int chunk_length_;  // Chunk size in samples.