gfe-relnote: (n/a) Add a Bbr2Sender::GetTargetBytesInflight function and use it in Bbr2ProbeBwMode. Refactor only, no behavior change. PiperOrigin-RevId: 286216495 Change-Id: Ia9185ff0bc707973ed11908aa33d6f4dcce731ea

diff --git a/quic/core/congestion_control/bbr2_probe_bw.cc b/quic/core/congestion_control/bbr2_probe_bw.cc
index 4487cbf..6d5000b 100644
--- a/quic/core/congestion_control/bbr2_probe_bw.cc
+++ b/quic/core/congestion_control/bbr2_probe_bw.cc

@@ -245,11 +245,9 @@
     const Bbr2CongestionEvent& /*congestion_event*/) const {
   uint64_t rounds = Params().probe_bw_probe_max_rounds;
   if (Params().probe_bw_probe_reno_gain > 0.0) {
-    QuicByteCount bdp = model_->BDP(model_->BandwidthEstimate());
-    QuicByteCount inflight_bytes =
-        std::min(bdp, sender_->GetCongestionWindow());
-    uint64_t reno_rounds =
-        Params().probe_bw_probe_reno_gain * inflight_bytes / kDefaultTCPMSS;
+    QuicByteCount target_bytes_inflight = sender_->GetTargetBytesInflight();
+    uint64_t reno_rounds = Params().probe_bw_probe_reno_gain *
+                           target_bytes_inflight / kDefaultTCPMSS;
     rounds = std::min(rounds, reno_rounds);
   }
   bool result = cycle_.rounds_since_probe >= (rounds * probe_wait_fraction);

diff --git a/quic/core/congestion_control/bbr2_sender.cc b/quic/core/congestion_control/bbr2_sender.cc
index 3e707f3..d795ad1 100644
--- a/quic/core/congestion_control/bbr2_sender.cc
+++ b/quic/core/congestion_control/bbr2_sender.cc

@@ -312,6 +312,11 @@
                 << ", CWND: " << GetCongestionWindow();
 }
 
+QuicByteCount Bbr2Sender::GetTargetBytesInflight() const {
+  QuicByteCount bdp = model_.BDP(model_.BandwidthEstimate());
+  return std::min(bdp, GetCongestionWindow());
+}
+
 void Bbr2Sender::PopulateConnectionStats(QuicConnectionStats* stats) const {
   stats->num_ack_aggregation_epochs = model_.num_ack_aggregation_epochs();
 }

diff --git a/quic/core/congestion_control/bbr2_sender.h b/quic/core/congestion_control/bbr2_sender.h
index 4cfd34c..2bba285 100644
--- a/quic/core/congestion_control/bbr2_sender.h
+++ b/quic/core/congestion_control/bbr2_sender.h

@@ -97,6 +97,9 @@
     return cwnd_limits().Min();
   }
 
+  // Returns the min of BDP and congestion window.
+  QuicByteCount GetTargetBytesInflight() const;
+
   struct QUIC_EXPORT_PRIVATE DebugState {
     Bbr2Mode mode;