Internal change PiperOrigin-RevId: 424125792

diff --git a/quic/core/congestion_control/pacing_sender.h b/quic/core/congestion_control/pacing_sender.h
index d473a38..b2401a2 100644
--- a/quic/core/congestion_control/pacing_sender.h
+++ b/quic/core/congestion_control/pacing_sender.h

@@ -79,6 +79,8 @@
     return {ideal_next_packet_send_time_, allow_burst};
   }
 
+  uint32_t initial_burst_size() const { return initial_burst_size_; }
+
  protected:
   uint32_t lumpy_tokens() const { return lumpy_tokens_; }
 

diff --git a/quic/core/congestion_control/send_algorithm_interface.h b/quic/core/congestion_control/send_algorithm_interface.h
index 2fa1217..4271603 100644
--- a/quic/core/congestion_control/send_algorithm_interface.h
+++ b/quic/core/congestion_control/send_algorithm_interface.h

@@ -33,27 +33,28 @@
  public:
   // Network Params for AdjustNetworkParameters.
   struct QUIC_NO_EXPORT NetworkParams {
-    NetworkParams()
-        : NetworkParams(QuicBandwidth::Zero(), QuicTime::Delta::Zero(), false) {
-    }
+    NetworkParams() = default;
     NetworkParams(const QuicBandwidth& bandwidth,
                   const QuicTime::Delta& rtt,
                   bool allow_cwnd_to_decrease)
         : bandwidth(bandwidth),
           rtt(rtt),
           allow_cwnd_to_decrease(allow_cwnd_to_decrease) {}
+    explicit NetworkParams(int burst_token) : burst_token(burst_token) {}
 
     bool operator==(const NetworkParams& other) const {
       return bandwidth == other.bandwidth && rtt == other.rtt &&
              max_initial_congestion_window ==
                  other.max_initial_congestion_window &&
+             burst_token == other.burst_token &&
              allow_cwnd_to_decrease == other.allow_cwnd_to_decrease;
     }
 
-    QuicBandwidth bandwidth;
-    QuicTime::Delta rtt;
+    QuicBandwidth bandwidth = QuicBandwidth::Zero();
+    QuicTime::Delta rtt = QuicTime::Delta::Zero();
     int max_initial_congestion_window = 0;
-    bool allow_cwnd_to_decrease;
+    int burst_token = 0;
+    bool allow_cwnd_to_decrease = false;
   };
 
   static SendAlgorithmInterface* Create(

diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index a700fd7..471ecd1 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h

@@ -6,6 +6,8 @@
 
 #ifdef QUIC_FLAG
 
+QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_set_burst_token, false)
+
 QUIC_FLAG(FLAGS_quic_restart_flag_quic_offload_pacing_to_usps2, false)
 // A testonly reloadable flag that will always default to false.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_testonly_default_false, false)

diff --git a/quic/core/quic_sent_packet_manager.cc b/quic/core/quic_sent_packet_manager.cc
index 4c5026c..eae919c 100644
--- a/quic/core/quic_sent_packet_manager.cc
+++ b/quic/core/quic_sent_packet_manager.cc

@@ -392,6 +392,18 @@
 
 void QuicSentPacketManager::AdjustNetworkParameters(
     const SendAlgorithmInterface::NetworkParams& params) {
+  if (params.burst_token != 0) {
+    if (using_pacing_) {
+      QUIC_RELOADABLE_FLAG_COUNT(quic_set_burst_token);
+      int old_burst_size = pacing_sender_.initial_burst_size();
+      pacing_sender_.SetBurstTokens(params.burst_token);
+      if (debug_delegate_ != nullptr) {
+        debug_delegate_->OnAdjustBurstSize(old_burst_size,
+                                           pacing_sender_.initial_burst_size());
+      }
+    }
+    return;
+  }
   const QuicBandwidth& bandwidth = params.bandwidth;
   const QuicTime::Delta& rtt = params.rtt;
   if (!rtt.IsZero()) {

diff --git a/quic/core/quic_sent_packet_manager.h b/quic/core/quic_sent_packet_manager.h
index e4a7036..b1efb81 100644
--- a/quic/core/quic_sent_packet_manager.h
+++ b/quic/core/quic_sent_packet_manager.h

@@ -80,6 +80,9 @@
                                            QuicByteCount /*old_cwnd*/,
                                            QuicByteCount /*new_cwnd*/) {}
 
+    virtual void OnAdjustBurstSize(int /*old_burst_size*/,
+                                   int /*new_burst_size*/) {}
+
     virtual void OnOvershootingDetected() {}
   };
 

diff --git a/quic/test_tools/quic_sent_packet_manager_peer.cc b/quic/test_tools/quic_sent_packet_manager_peer.cc
index 7d1ba86..3223516 100644
--- a/quic/test_tools/quic_sent_packet_manager_peer.cc
+++ b/quic/test_tools/quic_sent_packet_manager_peer.cc

@@ -180,6 +180,12 @@
 }
 
 // static
+int QuicSentPacketManagerPeer::GetPacerInitialBurstSize(
+    QuicSentPacketManager* sent_packet_manager) {
+  return sent_packet_manager->pacing_sender_.initial_burst_size_;
+}
+
+// static
 void QuicSentPacketManagerPeer::SetNextPacedPacketTime(
     QuicSentPacketManager* sent_packet_manager,
     QuicTime time) {

diff --git a/quic/test_tools/quic_sent_packet_manager_peer.h b/quic/test_tools/quic_sent_packet_manager_peer.h
index a39915f..35c5897 100644
--- a/quic/test_tools/quic_sent_packet_manager_peer.h
+++ b/quic/test_tools/quic_sent_packet_manager_peer.h

@@ -85,6 +85,9 @@
 
   static void DisablePacerBursts(QuicSentPacketManager* sent_packet_manager);
 
+  static int GetPacerInitialBurstSize(
+      QuicSentPacketManager* sent_packet_manager);
+
   static void SetNextPacedPacketTime(QuicSentPacketManager* sent_packet_manager,
                                      QuicTime time);