Refactor BBR2/BBR3 initialization and inline some methods. Bbr2NetworkModel now initializes its gains from Bbr2Params' startup values, removing redundant constructor arguments. PiperOrigin-RevId: 903383815

diff --git a/quiche/quic/core/congestion_control/bbr2_misc.cc b/quiche/quic/core/congestion_control/bbr2_misc.cc
index 123dd1d..2ec5df5 100644
--- a/quiche/quic/core/congestion_control/bbr2_misc.cc
+++ b/quiche/quic/core/congestion_control/bbr2_misc.cc

@@ -84,7 +84,6 @@
 Bbr2NetworkModel::Bbr2NetworkModel(const Bbr2Params* params,
                                    QuicTime::Delta initial_rtt,
                                    QuicTime initial_rtt_timestamp,
-                                   float cwnd_gain, float pacing_gain,
                                    const BandwidthSampler* old_sampler)
     : params_(params),
       bandwidth_sampler_([](QuicRoundTripCount max_height_tracker_window_length,
@@ -96,8 +95,8 @@
                                 max_height_tracker_window_length);
       }(params->initial_max_ack_height_filter_window, old_sampler)),
       min_rtt_filter_(initial_rtt, initial_rtt_timestamp),
-      cwnd_gain_(cwnd_gain),
-      pacing_gain_(pacing_gain) {}
+      cwnd_gain_(params->startup_cwnd_gain),
+      pacing_gain_(params->startup_pacing_gain) {}
 
 void Bbr2NetworkModel::OnPacketSent(QuicTime sent_time,
                                     QuicByteCount bytes_in_flight,

diff --git a/quiche/quic/core/congestion_control/bbr2_misc.h b/quiche/quic/core/congestion_control/bbr2_misc.h
index 17f3c3c..3da0471 100644
--- a/quiche/quic/core/congestion_control/bbr2_misc.h
+++ b/quiche/quic/core/congestion_control/bbr2_misc.h

@@ -361,8 +361,8 @@
 class QUICHE_EXPORT Bbr2NetworkModel {
  public:
   Bbr2NetworkModel(const Bbr2Params* params, QuicTime::Delta initial_rtt,
-                   QuicTime initial_rtt_timestamp, float cwnd_gain,
-                   float pacing_gain, const BandwidthSampler* old_sampler);
+                   QuicTime initial_rtt_timestamp,
+                   const BandwidthSampler* old_sampler);
 
   void OnPacketSent(QuicTime sent_time, QuicByteCount bytes_in_flight,
                     QuicPacketNumber packet_number, QuicByteCount bytes,

diff --git a/quiche/quic/core/congestion_control/bbr2_sender.cc b/quiche/quic/core/congestion_control/bbr2_sender.cc
index 30170a6..730a781 100644
--- a/quiche/quic/core/congestion_control/bbr2_sender.cc
+++ b/quiche/quic/core/congestion_control/bbr2_sender.cc

@@ -67,8 +67,6 @@
               max_cwnd_in_packets * kDefaultTCPMSS),
       model_(&params_, rtt_stats->SmoothedOrInitialRtt(),
              rtt_stats->last_update_time(),
-             /*cwnd_gain=*/1.0,
-             /*pacing_gain=*/kInitialPacingGain,
              old_sender ? &old_sender->sampler_ : nullptr),
       initial_cwnd_(cwnd_limits().ApplyLimits(
           (old_sender) ? old_sender->GetCongestionWindow()
@@ -339,7 +337,7 @@
   }
   if (congestion_event.bytes_in_flight == 0 &&
       params().avoid_unnecessary_probe_rtt) {
-    OnEnterQuiescence(event_time);
+    last_quiescence_start_ = event_time;
   }
 
   QUIC_DVLOG(3)
@@ -459,8 +457,7 @@
 }
 
 bool Bbr2Sender::CanSend(QuicByteCount bytes_in_flight) {
-  const bool result = bytes_in_flight < GetCongestionWindow();
-  return result;
+  return bytes_in_flight < GetCongestionWindow();
 }
 
 QuicByteCount Bbr2Sender::GetCongestionWindow() const {
@@ -492,10 +489,6 @@
   stats->num_ack_aggregation_epochs = model_.num_ack_aggregation_epochs();
 }
 
-void Bbr2Sender::OnEnterQuiescence(QuicTime now) {
-  last_quiescence_start_ = now;
-}
-
 void Bbr2Sender::OnExitQuiescence(QuicTime now) {
   if (last_quiescence_start_ != QuicTime::Zero()) {
     Bbr2Mode next_mode = BBR2_MODE_DISPATCH(

diff --git a/quiche/quic/core/congestion_control/bbr2_sender.h b/quiche/quic/core/congestion_control/bbr2_sender.h
index f625919..d73a702 100644
--- a/quiche/quic/core/congestion_control/bbr2_sender.h
+++ b/quiche/quic/core/congestion_control/bbr2_sender.h

@@ -124,7 +124,6 @@
   void UpdatePacingRate(QuicByteCount bytes_acked);
   void UpdateCongestionWindow(QuicByteCount bytes_acked);
   QuicByteCount GetTargetCongestionWindow(float gain) const;
-  void OnEnterQuiescence(QuicTime now);
   void OnExitQuiescence(QuicTime now);
 
   // Helper function for BBR2_MODE_DISPATCH.

diff --git a/quiche/quic/core/congestion_control/bbr3_sender.cc b/quiche/quic/core/congestion_control/bbr3_sender.cc
index cc3d570..e80e03e 100644
--- a/quiche/quic/core/congestion_control/bbr3_sender.cc
+++ b/quiche/quic/core/congestion_control/bbr3_sender.cc

@@ -42,8 +42,6 @@
               max_cwnd_in_packets * kDefaultTCPMSS),
       model_(&params_, rtt_stats->SmoothedOrInitialRtt(),
              rtt_stats->last_update_time(),
-             /*cwnd_gain=*/1.0,
-             /*pacing_gain=*/kInitialPacingGain,
              old_sender ? &old_sender->sampler_ : nullptr),
       initial_cwnd_(params_.cwnd_limits.ApplyLimits(
           (old_sender) ? old_sender->GetCongestionWindow()
@@ -371,7 +369,7 @@
   }
   if (congestion_event.bytes_in_flight == 0 &&
       params_.avoid_unnecessary_probe_rtt) {
-    OnEnterQuiescence(event_time);
+    last_quiescence_start_ = event_time;
   }
 
   QUIC_DVLOG(3)
@@ -491,8 +489,7 @@
 }
 
 bool Bbr3Sender::CanSend(QuicByteCount bytes_in_flight) {
-  const bool result = bytes_in_flight < GetCongestionWindow();
-  return result;
+  return bytes_in_flight < GetCongestionWindow();
 }
 
 QuicByteCount Bbr3Sender::GetCongestionWindow() const {
@@ -524,10 +521,6 @@
   stats->num_ack_aggregation_epochs = model_.num_ack_aggregation_epochs();
 }
 
-void Bbr3Sender::OnEnterQuiescence(QuicTime now) {
-  last_quiescence_start_ = now;
-}
-
 void Bbr3Sender::LeaveStartup(QuicTime now) {
   connection_stats_->slowstart_duration.Stop(now);
   // Clear bandwidth_lo if it's set during STARTUP.
@@ -801,7 +794,7 @@
     return;
   }
 
-  if (HasStayedLongEnoughInProbeDown(congestion_event)) {
+  if (HasPhaseLasted(model_.MinRtt(), congestion_event)) {
     QUIC_DVLOG(3) << this << " Proportional time based PROBE_DOWN exit";
     EnterProbeCruise(congestion_event.event_time);
     return;
@@ -918,11 +911,6 @@
   return false;
 }
 
-bool Bbr3Sender::HasStayedLongEnoughInProbeDown(
-    const Bbr2CongestionEvent& congestion_event) const {
-  return HasPhaseLasted(model_.MinRtt(), congestion_event);
-}
-
 bool Bbr3Sender::HasCycleLasted(
     QuicTime::Delta duration,
     const Bbr2CongestionEvent& congestion_event) const {

diff --git a/quiche/quic/core/congestion_control/bbr3_sender.h b/quiche/quic/core/congestion_control/bbr3_sender.h
index 1b4666f..f6e0f9e 100644
--- a/quiche/quic/core/congestion_control/bbr3_sender.h
+++ b/quiche/quic/core/congestion_control/bbr3_sender.h

@@ -129,7 +129,6 @@
   Bbr2Mode OnCongestionEventDrain(const Bbr2CongestionEvent& congestion_event);
   QuicByteCount DrainTarget() const;
 
-  void OnEnterQuiescence(QuicTime now);
   void OnExitQuiescence(QuicTime now);
 
   Bbr2Mode OnCongestionEventProbeBw(
@@ -161,8 +160,6 @@
 
   bool IsTimeToProbeBandwidth(
       const Bbr2CongestionEvent& congestion_event) const;
-  bool HasStayedLongEnoughInProbeDown(
-      const Bbr2CongestionEvent& congestion_event) const;
   bool HasCycleLasted(QuicTime::Delta duration,
                       const Bbr2CongestionEvent& congestion_event) const;
   bool HasPhaseLasted(QuicTime::Delta duration,