Change TWCC send interval to reduce overhead on low BW situations.

webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.h

Index: webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.h
diff --git a/webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.h b/webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.h
index 127886300d8f95c2fd14d78ebc0ffae9ee5c1094..1f6be50ecb0f033ed0fa2fb41baa7a8a10614745 100644
--- a/webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.h
+++ b/webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy.h
@@ -12,9 +12,11 @@
 #define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_REMOTE_ESTIMATOR_PROXY_H_
 
 #include <map>
+#include <memory>
 #include <vector>
 
 #include "webrtc/base/criticalsection.h"
+#include "webrtc/base/optional.h"
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h"
 
@@ -47,8 +49,11 @@ class RemoteEstimatorProxy : public RemoteBitrateEstimator {
   void SetMinBitrate(int min_bitrate_bps) override {}
   int64_t TimeUntilNextProcess() override;
   void Process() override;
+  void OnBitrateChanged(int bitrate);
 
-  static const int kDefaultProcessIntervalMs;
+  static const int kMinSendIntervalMs;
+  static const int kMaxSendIntervalMs;
+  static const int kDefaultSendIntervalMs;
   static const int kBackWindowMs;
 
  private:
@@ -68,6 +73,7 @@ class RemoteEstimatorProxy : public RemoteBitrateEstimator {
   int64_t window_start_seq_ GUARDED_BY(&lock_);
   // Map unwrapped seq -> time.
   std::map<int64_t, int64_t> packet_arrival_times_ GUARDED_BY(&lock_);
+  rtc::Optional<int> bitrate_bps_;
 };
 
 }  // namespace webrtc