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

webrtc/modules/audio_processing/echo_detector/moving_max_unittest.cc

Index: webrtc/modules/audio_processing/echo_detector/moving_max_unittest.cc
diff --git a/webrtc/modules/audio_processing/echo_detector/moving_max_unittest.cc b/webrtc/modules/audio_processing/echo_detector/moving_max_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..720010d0026df0b28ce417648e69fc2aed726da0
--- /dev/null
+++ b/webrtc/modules/audio_processing/echo_detector/moving_max_unittest.cc
@@ -0,0 +1,67 @@
+/*
+ *  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.
+ */
+
+#include "webrtc/modules/audio_processing/echo_detector/moving_max.h"
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+
+// Test if the maximum is correctly found.
+TEST(MovingMaxTests, SimpleTest) {
+  MovingMax test_moving_max(5);
+  test_moving_max.Update(1.0f);
+  test_moving_max.Update(1.1f);
+  test_moving_max.Update(1.9f);
+  test_moving_max.Update(1.87f);
+  test_moving_max.Update(1.89f);
+  EXPECT_EQ(1.9f, test_moving_max.max());
+}
+
+// Test if values fall out of the window when expected.
+TEST(MovingMaxTests, SlidingWindowTest) {
+  MovingMax test_moving_max(5);
+  test_moving_max.Update(1.0f);
+  test_moving_max.Update(1.9f);
+  test_moving_max.Update(1.7f);
+  test_moving_max.Update(1.87f);
+  test_moving_max.Update(1.89f);
+  test_moving_max.Update(1.3f);
+  test_moving_max.Update(1.2f);
+  EXPECT_LT(test_moving_max.max(), 1.9f);
+}
+
+// Test if Clear() works as expected.
+TEST(MovingMaxTests, ClearTest) {
+  MovingMax test_moving_max(5);
+  test_moving_max.Update(1.0f);
+  test_moving_max.Update(1.1f);
+  test_moving_max.Update(1.9f);
+  test_moving_max.Update(1.87f);
+  test_moving_max.Update(1.89f);
+  EXPECT_EQ(1.9f, test_moving_max.max());
+  test_moving_max.Clear();
+  EXPECT_EQ(0.f, test_moving_max.max());
+}
+
+// Test the decay of the estimated maximum.
+TEST(MovingMaxTests, DecayTest) {
+  MovingMax test_moving_max(1);
+  test_moving_max.Update(1.0f);
+  float previous_value = 1.0f;
+  for (int i = 0; i < 500; i++) {
+    test_moving_max.Update(0.0f);
+    EXPECT_LT(test_moving_max.max(), previous_value);
+    EXPECT_GT(test_moving_max.max(), 0.0f);
+    previous_value = test_moving_max.max();
+  }
+  EXPECT_LT(test_moving_max.max(), 0.01f);
+}
+
+}  // namespace webrtc