Deprecate --gfe2_reloadable_flag_quic_bbr2_startup_probe_up_loss_events.

PiperOrigin-RevId: 475293159

quiche/quic/core/congestion_control/bbr2_sender.cc

diff --git a/quiche/quic/core/congestion_control/bbr2_sender.cc b/quiche/quic/core/congestion_control/bbr2_sender.cc
index 208858b..35bfe44 100644
--- a/quiche/quic/core/congestion_control/bbr2_sender.cc
+++ b/quiche/quic/core/congestion_control/bbr2_sender.cc
@@ -206,9 +206,7 @@
     params_.probe_up_includes_acks_after_cwnd_limited = true;
   }
 
-  if (GetQuicReloadableFlag(quic_bbr2_startup_probe_up_loss_events) &&
-      ContainsQuicTag(connection_options, kB206)) {
-    QUIC_RELOADABLE_FLAG_COUNT(quic_bbr2_startup_probe_up_loss_events);
+  if (ContainsQuicTag(connection_options, kB206)) {
     params_.startup_full_loss_count = params_.probe_bw_full_loss_count;
   }
 }

quiche/quic/core/congestion_control/bbr2_simulator_test.cc

diff --git a/quiche/quic/core/congestion_control/bbr2_simulator_test.cc b/quiche/quic/core/congestion_control/bbr2_simulator_test.cc
index 07f8121..06a9876 100644
--- a/quiche/quic/core/congestion_control/bbr2_simulator_test.cc
+++ b/quiche/quic/core/congestion_control/bbr2_simulator_test.cc
@@ -519,7 +519,6 @@
 }
 
 TEST_F(Bbr2DefaultTopologyTest, SimpleTransferB206) {
-  SetQuicReloadableFlag(quic_bbr2_startup_probe_up_loss_events, true);
   SetConnectionOption(kB206);
   DefaultTopologyParams params;
   CreateNetwork(params);

quiche/quic/core/quic_flags_list.h

diff --git a/quiche/quic/core/quic_flags_list.h b/quiche/quic/core/quic_flags_list.h
index 4b4cfd7..3cb93c4 100644
--- a/quiche/quic/core/quic_flags_list.h
+++ b/quiche/quic/core/quic_flags_list.h
@@ -91,8 +91,6 @@
 QUIC_FLAG(quic_restart_flag_quic_abstract_connection_id_generator, true)
 // Store original QUIC connection IDs in the dispatcher\'s map
 QUIC_FLAG(quic_restart_flag_quic_map_original_connection_ids2, true)
-// When the flag is true, exit STARTUP after the same number of loss events as PROBE_UP.
-QUIC_FLAG(quic_reloadable_flag_quic_bbr2_startup_probe_up_loss_events, true)
 // When true, defaults to BBR congestion control instead of Cubic.
 QUIC_FLAG(quic_reloadable_flag_quic_default_to_bbr, false)
 // When true, prevents QUIC\'s PacingSender from generating bursts when the congestion controller is CWND limited and not pacing limited.