Added a new echo likelihood stat that reports the maximum value from a previous time period.

webrtc/modules/audio_processing/echo_detector/moving_max.h

+/*
+ *  Copyright (c) 2017 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_ECHO_DETECTOR_MOVING_MAX_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_ECHO_DETECTOR_MOVING_MAX_H_
+
+#include <deque>
+#include <vector>
+
+namespace webrtc {
+
+class MovingMax {
+ public:
+  explicit MovingMax(size_t window_size);
+  ~MovingMax();
+
+  // Add a new likelihood to the buffer. This will automatically remove the

[the sun, 2017/01/13 14:51:23]

Comments need updating. Since it's a generic class, skip the talk about a
likelihood...

[ivoc, 2017/01/13 15:08:42]

I removed the comments for Update() and max(), since if I remove the talk about
likelihoods there isn't anything important left :)

+  // oldest likelihood value from the buffer.
+  void Update(float value);
+  // Return the maximum likelihood value in the buffer.
+  float max() const;
+  // Fill the buffer with zeros.
+  void Clear();
+
+ private:
+  float max_value_ = 0.f;
+  size_t counter_ = 0;
+  size_t window_size_;

[the sun, 2017/01/13 14:51:23]

It's a good idea to always init everything, regardless if you also set it in the
ctor

[ivoc, 2017/01/13 15:08:41]

Since zero is an illegal value, I set it to one by default now.

+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_ECHO_DETECTOR_MOVING_MAX_H_