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..457a3f4504159c2ad2da45ae2b94579d09c17be4 100644
--- a/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h
+++ b/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h
@@ -42,6 +42,8 @@ class AimdRateControl {
   void SetRtt(int64_t rtt);
   void Update(const RateControlInput* input, int64_t now_ms);
   void SetEstimate(int bitrate_bps, int64_t now_ms);
+  virtual rtc::Optional<int> GetNearMaxIncreaseRate() const;
+  virtual rtc::Optional<int> GetLastDecrease() const;
 
  private:
   // Update the target bitrate according based on, among other things,
@@ -70,6 +72,7 @@ class AimdRateControl {
   float avg_max_bitrate_kbps_;
   float var_max_bitrate_kbps_;
   RateControlState rate_control_state_;
+  RateControlState last_rate_control_state_;
   RateControlRegion rate_control_region_;
   int64_t time_last_bitrate_change_;
   RateControlInput current_input_;
@@ -79,6 +82,9 @@ class AimdRateControl {
   float beta_;
   int64_t rtt_;
   bool in_experiment_;
+  rtc::Optional<int> near_max_increase_rate_bps_;
+  rtc::Optional<int> last_decrease_;
+  rtc::Optional<int64_t> last_near_max_increase_rate_update_;
 };
 }  // namespace webrtc