Add functionality which limits the number of bytes on the network.

webrtc/modules/remote_bitrate_estimator/send_time_history.cc

Index: webrtc/modules/remote_bitrate_estimator/send_time_history.cc
diff --git a/webrtc/modules/remote_bitrate_estimator/send_time_history.cc b/webrtc/modules/remote_bitrate_estimator/send_time_history.cc
index 734a9207130116d78faec56706ac08f42f23a248..4cc7a7c1c20c5a009757ae1f5e27742448b6e0f0 100644
--- a/webrtc/modules/remote_bitrate_estimator/send_time_history.cc
+++ b/webrtc/modules/remote_bitrate_estimator/send_time_history.cc
@@ -52,6 +52,9 @@ bool SendTimeHistory::GetFeedback(PacketFeedback* packet_feedback,
   RTC_DCHECK(packet_feedback);
   int64_t unwrapped_seq_num =
       seq_num_unwrapper_.Unwrap(packet_feedback->sequence_number);
+  latest_acked_seq_num_.emplace(
+      std::max(unwrapped_seq_num, latest_acked_seq_num_.value_or(0)));
+  RTC_DCHECK_GE(*latest_acked_seq_num_, 0);
   auto it = history_.find(unwrapped_seq_num);
   if (it == history_.end())
     return false;
@@ -66,4 +69,21 @@ bool SendTimeHistory::GetFeedback(PacketFeedback* packet_feedback,
   return true;
 }
 
+size_t SendTimeHistory::GetOutstandingBytes(uint16_t local_net_id,
+                                            uint16_t remote_net_id) const {
+  size_t outstanding_bytes = 0;
+  auto unacked_it = history_.begin();
+  if (latest_acked_seq_num_) {
+    unacked_it = history_.lower_bound(*latest_acked_seq_num_);
+  }
+  for (; unacked_it != history_.end(); ++unacked_it) {
+    if (unacked_it->second.local_net_id == local_net_id &&
+        unacked_it->second.remote_net_id == remote_net_id &&
+        unacked_it->second.send_time_ms >= 0) {
+      outstanding_bytes += unacked_it->second.payload_size;
+    }
+  }
+  return outstanding_bytes;
+}
+
 }  // namespace webrtc