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

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

Index: webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter_unittest.cc
diff --git a/webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter_unittest.cc b/webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..588b7c10ad7de4235f4d077cbe4294a772976eb5
--- /dev/null
+++ b/webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter_unittest.cc
@@ -0,0 +1,43 @@
+/*
+ *  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"
+
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+namespace testing {
+namespace bwe {
+TEST(MinRttFilterTest, InitializationCheck) {
+  MinRttFilter min_rtt_filter;
+  EXPECT_FALSE(min_rtt_filter.min_rtt());
+  EXPECT_EQ(min_rtt_filter.discovery_time(), 0);
+}
+
+TEST(MinRttFilterTest, AddRttSample) {
+  MinRttFilter min_rtt_filter;
+  min_rtt_filter.add_rtt_sample(120, 5);
+  EXPECT_EQ(min_rtt_filter.min_rtt(), 120);
+  EXPECT_EQ(min_rtt_filter.discovery_time(), 5);
+  min_rtt_filter.add_rtt_sample(121, 6);
+  EXPECT_EQ(min_rtt_filter.discovery_time(), 5);
+  min_rtt_filter.add_rtt_sample(119, 7);
+  EXPECT_EQ(min_rtt_filter.discovery_time(), 7);
+}
+
+TEST(MinRttFilterTest, MinRttExpired) {
+  MinRttFilter min_rtt_filter;
+  min_rtt_filter.add_rtt_sample(120, 5);
+  EXPECT_EQ(min_rtt_filter.min_rtt_expired(10, 5), true);
+  EXPECT_EQ(min_rtt_filter.min_rtt_expired(9, 5), false);
+}
+}  // namespace bwe
+}  // namespace testing
+}  // namespace webrtc