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diff --git a/third_party/libwebrtc/rtc_base/numerics/moving_average.h b/third_party/libwebrtc/rtc_base/numerics/moving_average.h
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+/*
+ *  Copyright (c) 2018 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 RTC_BASE_NUMERICS_MOVING_AVERAGE_H_
+#define RTC_BASE_NUMERICS_MOVING_AVERAGE_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <vector>
+
+#include "absl/types/optional.h"
+
+namespace rtc {
+
+// Calculates average over fixed size window. If there are less than window
+// size elements, calculates average of all inserted so far elements.
+//
+class MovingAverage {
+ public:
+  // Maximum supported window size is 2^32 - 1.
+  explicit MovingAverage(size_t window_size);
+  ~MovingAverage();
+  // MovingAverage is neither copyable nor movable.
+  MovingAverage(const MovingAverage&) = delete;
+  MovingAverage& operator=(const MovingAverage&) = delete;
+
+  // Adds new sample. If the window is full, the oldest element is pushed out.
+  void AddSample(int sample);
+
+  // Returns rounded down average of last `window_size` elements or all
+  // elements if there are not enough of them. Returns nullopt if there were
+  // no elements added.
+  absl::optional<int> GetAverageRoundedDown() const;
+
+  // Same as above but rounded to the closest integer.
+  absl::optional<int> GetAverageRoundedToClosest() const;
+
+  // Returns unrounded average over the window.
+  absl::optional<double> GetUnroundedAverage() const;
+
+  // Resets to the initial state before any elements were added.
+  void Reset();
+
+  // Returns number of elements in the window.
+  size_t Size() const;
+
+ private:
+  // Total number of samples added to the class since last reset.
+  size_t count_ = 0;
+  // Sum of the samples in the moving window.
+  int64_t sum_ = 0;
+  // Circular buffer for all the samples in the moving window.
+  // Size is always `window_size`
+  std::vector<int> history_;
+};
+
+}  // namespace rtc
+#endif  // RTC_BASE_NUMERICS_MOVING_AVERAGE_H_