Added implementation of three classes in BBR,with unit-tests.

webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter.cc

Index: webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter.cc
diff --git a/webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter.cc b/webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..64df98e4f385084d8ee58d2d1783e22fc18ff3d3
--- /dev/null
+++ b/webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter.cc
@@ -0,0 +1,24 @@
+/*
+ *  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/remote_bitrate_estimator/test/estimators/min_rtt_filter.h"

[philipel, 2017/07/06 12:15:15]

This class is small enough to not have a .cc file, inline everything in the .h
file instead.

[gnish1, 2017/07/07 13:43:34]

Done.

+
+namespace webrtc {
+namespace testing {
+namespace bwe {
+MinRttFilter::MinRttFilter() : min_rtt_(10000000), discovery_time_(0) {}

[philipel, 2017/07/06 12:15:16]

Use std::numeric_limits<int64_t>::max() instead of 10000000.

[gnish1, 2017/07/07 13:43:34]

Done.

+MinRttFilter::~MinRttFilter() {}
+void MinRttFilter::UpdateMinRtt(int64_t min_rtt) {

[philipel, 2017/07/06 12:15:16]

Don't you want a AddRttSample(int64_t rtt_ms, int64_t now_ms) function instead?
Currently this class does not have the functionality I would expect of a min
filter.

[gnish1, 2017/07/07 13:43:34]

Done.

+  min_rtt_ = min_rtt;

[stefan-webrtc, 2017/07/06 13:39:25]

This doesn't look like a min filter?

[gnish1, 2017/07/07 13:43:34]

Done.

+}
+}  // namespace bwe
+}  // namespace testing
+}  // namespace webrtc