Bump to WebRTC M120 release

Some API deprecation -- ExperimentalAgc and ExperimentalNs are gone.
We're continuing to carry iSAC even though it's gone upstream, but maybe
we'll want to drop that soon.

webrtc/modules/audio_processing/agc2/rnn_vad/rnn_fc.h

@@ -0,0 +1,72 @@
+/*
+ *  Copyright (c) 2020 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 MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_RNN_FC_H_
+#define MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_RNN_FC_H_
+
+#include <array>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "api/array_view.h"
+#include "api/function_view.h"
+#include "modules/audio_processing/agc2/cpu_features.h"
+#include "modules/audio_processing/agc2/rnn_vad/vector_math.h"
+
+namespace webrtc {
+namespace rnn_vad {
+
+// Activation function for a neural network cell.
+enum class ActivationFunction { kTansigApproximated, kSigmoidApproximated };
+
+// Maximum number of units for an FC layer.
+constexpr int kFullyConnectedLayerMaxUnits = 24;
+
+// Fully-connected layer with a custom activation function which owns the output
+// buffer.
+class FullyConnectedLayer {
+ public:
+  // Ctor. `output_size` cannot be greater than `kFullyConnectedLayerMaxUnits`.
+  FullyConnectedLayer(int input_size,
+                      int output_size,
+                      rtc::ArrayView<const int8_t> bias,
+                      rtc::ArrayView<const int8_t> weights,
+                      ActivationFunction activation_function,
+                      const AvailableCpuFeatures& cpu_features,
+                      absl::string_view layer_name);
+  FullyConnectedLayer(const FullyConnectedLayer&) = delete;
+  FullyConnectedLayer& operator=(const FullyConnectedLayer&) = delete;
+  ~FullyConnectedLayer();
+
+  // Returns the size of the input vector.
+  int input_size() const { return input_size_; }
+  // Returns the pointer to the first element of the output buffer.
+  const float* data() const { return output_.data(); }
+  // Returns the size of the output buffer.
+  int size() const { return output_size_; }
+
+  // Computes the fully-connected layer output.
+  void ComputeOutput(rtc::ArrayView<const float> input);
+
+ private:
+  const int input_size_;
+  const int output_size_;
+  const std::vector<float> bias_;
+  const std::vector<float> weights_;
+  const VectorMath vector_math_;
+  rtc::FunctionView<float(float)> activation_function_;
+  // Over-allocated array with size equal to `output_size_`.
+  std::array<float, kFullyConnectedLayerMaxUnits> output_;
+};
+
+}  // namespace rnn_vad
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AGC2_RNN_VAD_RNN_FC_H_