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..64f2bfa733c66fc48c4960556c03e2e3babdd8d4
--- /dev/null
+++ b/webrtc/modules/remote_bitrate_estimator/test/estimators/min_rtt_filter_unittest.cc
@@ -0,0 +1,37 @@
+/*
+ *  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_EQ(min_rtt_filter.min_rtt(), 10000000);
+  EXPECT_EQ(min_rtt_filter.discovery_time(), 0);
+}
+
+TEST(MinRttFilterTest, MinRttUpdate) {
+  MinRttFilter min_rtt_filter;
+  min_rtt_filter.UpdateMinRtt(120);
+  EXPECT_EQ(min_rtt_filter.min_rtt(), 120);
+}
+
+TEST(MinRttFilterTest, DiscoveryTimeUpdate) {
+  MinRttFilter min_rtt_filter;
+  min_rtt_filter.set_discovery_time(1240);
+  EXPECT_EQ(min_rtt_filter.discovery_time(), 1240);
+}
+}  // namespace bwe
+}  // namespace testing
+}  // namespace webrtc