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

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

Index: webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc
diff --git a/webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc b/webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc
index bc0d370bca5dc9ecff8af60dcda9fe8c022d60a3..869141f05a20056a0db6097486b748245d2fd9d0 100644
--- a/webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc
+++ b/webrtc/modules/remote_bitrate_estimator/test/estimators/congestion_window_unittest.cc
@@ -46,35 +46,38 @@ TEST(CongestionWindowTest, DataInflight) {
 TEST(CongestionWindowTest, ZeroBandwidthDelayProduct) {
   CongestionWindow congestion_window;
   int64_t target_congestion_window =
-      congestion_window.GetTargetCongestionWindow(100, 0, 2.885f);
+      congestion_window.GetTargetCongestionWindow(
+          100, rtc::Optional<int64_t>(0), 2.885f);
   EXPECT_EQ(target_congestion_window, 2.885f * kStartingCongestionWindow);
 }
 
 TEST(CongestionWindowTest, BelowMinimumTargetCongestionWindow) {
   CongestionWindow congestion_window;
   int64_t target_congestion_window =
-      congestion_window.GetTargetCongestionWindow(100, 2, 2.885f);
+      congestion_window.GetTargetCongestionWindow(
+          100, rtc::Optional<int64_t>(2), 2.885f);
   EXPECT_EQ(target_congestion_window, kMinimumCongestionWindow);
 }
 
 TEST(CongestionWindowTest, AboveMinimumTargetCongestionWindow) {
   CongestionWindow congestion_window;
   int64_t target_congestion_window =
-      congestion_window.GetTargetCongestionWindow(100000, 2, 2.885f);
+      congestion_window.GetTargetCongestionWindow(
+          100000, rtc::Optional<int64_t>(2), 2.885f);
   EXPECT_EQ(target_congestion_window, 577000);
 }
 
 TEST(CongestionWindowTest, MinimumCongestionWindow) {
   CongestionWindow congestion_window;
-  int64_t cwnd = congestion_window.GetCongestionWindow(BbrBweSender::PROBE_RTT,
-                                                       100, 100, 2.885f);
+  int64_t cwnd = congestion_window.GetCongestionWindow(
+      BbrBweSender::PROBE_RTT, 100, rtc::Optional<int64_t>(100), 2.885f);
   EXPECT_EQ(cwnd, kMinimumCongestionWindow);
 }
 
 TEST(CongestionWindowTest, CalculateCongestionWindow) {
   CongestionWindow congestion_window;
-  int64_t cwnd = congestion_window.GetCongestionWindow(BbrBweSender::STARTUP,
-                                                       100, 100, 2.885f);
+  int64_t cwnd = congestion_window.GetCongestionWindow(
+      BbrBweSender::STARTUP, 100, rtc::Optional<int64_t>(100l), 2.885f);
   EXPECT_EQ(cwnd, 28850);
 }
 }  // namespace bwe