AEC3: Audility: Avoid the initialization of the noise estimator in pure zeroes signals at the render.

Bug: webrtc:9193,chromium:836790
Change-Id: Ic162dd72947f1d075b55df6725a17b66c782930a
Reviewed-on: https://webrtc-review.googlesource.com/73200
Reviewed-by: Per Åhgren <peah@webrtc.org>
Commit-Queue: Jesus de Vicente Pena <devicentepena@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23075}
diff --git a/modules/audio_processing/aec3/render_buffer.h b/modules/audio_processing/aec3/render_buffer.h
index 292cb9d..9419b30 100644
--- a/modules/audio_processing/aec3/render_buffer.h
+++ b/modules/audio_processing/aec3/render_buffer.h
@@ -45,14 +45,6 @@
     return spectrum_buffer_->buffer[position];
   }
 
-  // Get the spectrum directly from an index in the buffer.
-  rtc::ArrayView<const float> SpectrumAtIndex(int index) const {
-    RTC_CHECK_LT(index, spectrum_buffer_->size);
-    int position_bound = std::min(index, spectrum_buffer_->size - 1);
-    position_bound = std::max(0, position_bound);
-    return spectrum_buffer_->buffer[position_bound];
-  }
-
   // Returns the circular fft buffer.
   rtc::ArrayView<const FftData> GetFftBuffer() const {
     return fft_buffer_->buffer;
@@ -65,14 +57,6 @@
     return fft_buffer_->read;
   }
 
-  // Applies an offset to a buffer index and returns it.
-  int OffsetSpectrumIndex(int index, int offset) const {
-    return spectrum_buffer_->OffsetIndex(index, offset);
-  }
-
-  // Returns the write postion in the circular buffer.
-  int GetWritePositionSpectrum() const { return spectrum_buffer_->write; }
-
   // Returns the sum of the spectrums for a certain number of FFTs.
   void SpectralSum(size_t num_spectra,
                    std::array<float, kFftLengthBy2Plus1>* X2) const;
@@ -98,12 +82,13 @@
     return headroom;
   }
 
-  // Decreases an index that is used for accessing the buffer.
-  int DecIdx(int idx) const { return spectrum_buffer_->DecIndex(idx); }
 
   // Returns a reference to the spectrum buffer.
   const VectorBuffer& GetSpectrumBuffer() const { return *spectrum_buffer_; }
 
+  // Returns a reference to the block buffer.
+  const MatrixBuffer& GetBlockBuffer() const { return *block_buffer_; }
+
  private:
   const MatrixBuffer* const block_buffer_;
   const VectorBuffer* const spectrum_buffer_;