Add interval estimator to remote bitrate estimator

webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h

Index: webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h
diff --git a/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h b/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h
index 2b2e85bf911b0b16b80f092f78919a3b31c964c3..6e5410dd00f96a08193cf2640f89622809f345a7 100644
--- a/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h
+++ b/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h
@@ -43,6 +43,12 @@ class AimdRateControl {
   void Update(const RateControlInput* input, int64_t now_ms);
   void SetEstimate(int bitrate_bps, int64_t now_ms);
 
+  // Returns the increase rate which is used when used bandwidth is near the
+  // maximal available bandwidth.
+  virtual int GetNearMaxIncreaseRateBps() const;
+
+  virtual rtc::Optional<int> GetLastBitrateDecreaseBps() const;
+
  private:
   // Update the target bitrate according based on, among other things,
   // the current rate control state, the current target bitrate and the incoming
@@ -56,8 +62,7 @@ class AimdRateControl {
                          int64_t now_ms);
   uint32_t MultiplicativeRateIncrease(int64_t now_ms, int64_t last_ms,
                                       uint32_t current_bitrate_bps) const;
-  uint32_t AdditiveRateIncrease(int64_t now_ms, int64_t last_ms,
-                                int64_t response_time_ms) const;
+  uint32_t AdditiveRateIncrease(int64_t now_ms, int64_t last_ms) const;
   void UpdateChangePeriod(int64_t now_ms);
   void UpdateMaxBitRateEstimate(float incoming_bit_rate_kbps);
   void ChangeState(const RateControlInput& input, int64_t now_ms);
@@ -79,6 +84,7 @@ class AimdRateControl {
   float beta_;
   int64_t rtt_;
   bool in_experiment_;
+  rtc::Optional<int> last_decrease_;
 };
 }  // namespace webrtc