Added implementation of four functions in the BBR congestion controller.

webrtc/modules/remote_bitrate_estimator/test/estimators/bbr.h

Index: webrtc/modules/remote_bitrate_estimator/test/estimators/bbr.h
diff --git a/webrtc/modules/remote_bitrate_estimator/test/estimators/bbr.h b/webrtc/modules/remote_bitrate_estimator/test/estimators/bbr.h
index ebb2e6e5eea2ac6a65c516e2e09504823af79a19..399417a436cdf7d7c293ed649509566254031660 100644
--- a/webrtc/modules/remote_bitrate_estimator/test/estimators/bbr.h
+++ b/webrtc/modules/remote_bitrate_estimator/test/estimators/bbr.h
@@ -30,7 +30,7 @@ class MinRttFilter;
 class CongestionWindow;
 class BbrBweSender : public BweSender {
  public:
-  BbrBweSender();
+  explicit BbrBweSender(Clock* clock);
   virtual ~BbrBweSender();
   enum Mode {
     // Startup phase.
@@ -66,6 +66,16 @@ class BbrBweSender : public BweSender {
   void EnterProbeRtt(int64_t now);
   void TryExitingProbeRtt(int64_t now);
   void TryUpdatingCyclePhase(int64_t now);
+  void TryEnteringOrExitingProbeRtt(int64_t now);
+  Clock* const clock_;
+  Mode mode_;
+  std::unique_ptr<MaxBandwidthFilter> max_bandwidth_filter_;
+  uint64_t rt_count_;
+  uint64_t last_packet_sent_;
+  uint64_t round_trip_end_;
+  float pacing_gain_;
+  float congestion_window_gain_;
+  bool full_bandwidth_reached_;
 };
 
 class BbrBweReceiver : public BweReceiver {