Revert of Added first layer of the echo canceller 3 functionality

webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.h

Index: webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.h
diff --git a/webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.h b/webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.h
deleted file mode 100644
index 438a166eae0094451d39aa85166061900fff59e3..0000000000000000000000000000000000000000
--- a/webrtc/modules/audio_processing/aec3/cascaded_biquad_filter.h
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- *  Copyright (c) 2016 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.
- */
-
-#ifndef WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_CASCADED_BIQUAD_FILTER_H_
-#define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_CASCADED_BIQUAD_FILTER_H_
-
-#include <vector>
-
-#include "webrtc/base/array_view.h"
-#include "webrtc/base/constructormagic.h"
-
-namespace webrtc {
-
-// Applies a number of identical biquads in a cascaded manner. The filter
-// implementation is direct form 1.
-class CascadedBiQuadFilter {
- public:
-  struct BiQuadState {
-    BiQuadState() : x(), y() {}
-    float x[2];
-    float y[2];
-  };
-
-  struct BiQuadCoefficients {
-    float b[3];
-    float a[2];
-  };
-
-  CascadedBiQuadFilter(
-      const CascadedBiQuadFilter::BiQuadCoefficients& coefficients,
-      size_t num_biquads);
-  ~CascadedBiQuadFilter();
-  // Applies the biquads on the values in x in order to form the output in y.
-  void Process(rtc::ArrayView<const float> x, rtc::ArrayView<float> y);
-  // Applies the biquads on the values in y in an in-place manner.
-  void Process(rtc::ArrayView<float> y);
-
- private:
-  void ApplyBiQuad(rtc::ArrayView<const float> x,
-                   rtc::ArrayView<float> y,
-                   CascadedBiQuadFilter::BiQuadState* biquad_state);
-
-  std::vector<BiQuadState> biquad_states_;
-  const BiQuadCoefficients coefficients_;
-
-  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(CascadedBiQuadFilter);
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_CASCADED_BIQUAD_FILTER_H_