Compensate for the IntelligibilityEnhancer processing delay in high bands

webrtc/modules/audio_processing/intelligibility/intelligibility_utils.h

Index: webrtc/modules/audio_processing/intelligibility/intelligibility_utils.h
diff --git a/webrtc/modules/audio_processing/intelligibility/intelligibility_utils.h b/webrtc/modules/audio_processing/intelligibility/intelligibility_utils.h
index b5cc075140ff0bc97ea97b98445ac9e3ab531ab6..2566616f85bab868b6f54096f862c94bce3bb130 100644
--- a/webrtc/modules/audio_processing/intelligibility/intelligibility_utils.h
+++ b/webrtc/modules/audio_processing/intelligibility/intelligibility_utils.h
@@ -65,6 +65,20 @@ class GainApplier {
   std::vector<float> current_;
 };
 
+// Helper class to delay a signal by an integer number of samples.
+class DelayBuffer {
+ public:
+  DelayBuffer(size_t delay, size_t num_channels);
+
+  ~DelayBuffer();
+
+  void Delay(float* const* data, size_t length);
+
+ private:
+  std::vector<std::vector<float>> buffer_;
+  size_t read_index_;
+};
+
 }  // namespace intelligibility
 
 }  // namespace webrtc