Deprecate quic_check_alternate_reset_token.

NOT generated via copybara.

PiperOrigin-RevId: 986362749

quiche/common/quiche_feature_flags_list.h

diff --git a/quiche/common/quiche_feature_flags_list.h b/quiche/common/quiche_feature_flags_list.h
index ee777fe..fd3faaf 100755
--- a/quiche/common/quiche_feature_flags_list.h
+++ b/quiche/common/quiche_feature_flags_list.h
@@ -18,7 +18,6 @@
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_bbr_always_exit_startup_on_loss, false, false, "Lets BBRv1 exit STARTUP if a large number of packets was lost even if there is no non-app-limited samples. Similar to applying connection option B1AL to all connection.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_bbr_exit_startup_on_loss_network_param, false, true, "Enables adjustment of BBRv1's exit-startup-on-loss behavior on established connections via NetworkParams::enable_bbr_exit_startup_on_loss.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_block_until_settings_received_copt, true, true, "If enabled and a BSUS connection is received, blocks server connections until SETTINGS frame is received.")
-QUICHE_FLAG(bool, quiche_reloadable_flag_quic_check_alternate_reset_token, true, true, "When true, checks the stateless reset token on a path probe using the alternate path's token")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_clear_packet_on_serialization_failure, false, false, "If true, clear QuicPacketCreator state when serialization failure.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_client_check_blockage_before_on_can_write, false, false, "If true, quic clients will only call OnCanWrite() upon write events if the writer is unblocked.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_close_on_idle_timeout, false, false, "If true, closes the connection if it has exceeded the idle timeout when deciding whether to open a stream.")

quiche/quic/core/quic_connection.cc

diff --git a/quiche/quic/core/quic_connection.cc b/quiche/quic/core/quic_connection.cc
index 91f9426..7553af5 100644
--- a/quiche/quic/core/quic_connection.cc
+++ b/quiche/quic/core/quic_connection.cc
@@ -2381,27 +2381,19 @@
 bool QuicConnection::IsValidStatelessResetToken(
     const StatelessResetToken& token) const {
   QUICHE_DCHECK_EQ(perspective_, Perspective::IS_CLIENT);
-  if (GetQuicReloadableFlag(quic_check_alternate_reset_token)) {
-    if (IsDefaultPath(last_received_packet_info_.destination_address,
-                      last_received_packet_info_.source_address)) {
-      QUIC_RELOADABLE_FLAG_COUNT_N(quic_check_alternate_reset_token, 1, 2);
-      return default_path_.stateless_reset_token.has_value() &&
-             QuicUtils::AreStatelessResetTokensEqual(
-                 token, *default_path_.stateless_reset_token);
-    }
-    if (IsAlternativePath(last_received_packet_info_.destination_address,
-                          last_received_packet_info_.source_address)) {
-      QUIC_RELOADABLE_FLAG_COUNT_N(quic_check_alternate_reset_token, 2, 2);
-      return alternative_path_.stateless_reset_token.has_value() &&
-             QuicUtils::AreStatelessResetTokensEqual(
-                 token, *alternative_path_.stateless_reset_token);
-    }
-    return false;
-  } else {
+  if (IsDefaultPath(last_received_packet_info_.destination_address,
+                    last_received_packet_info_.source_address)) {
     return default_path_.stateless_reset_token.has_value() &&
            QuicUtils::AreStatelessResetTokensEqual(
                token, *default_path_.stateless_reset_token);
   }
+  if (IsAlternativePath(last_received_packet_info_.destination_address,
+                        last_received_packet_info_.source_address)) {
+    return alternative_path_.stateless_reset_token.has_value() &&
+           QuicUtils::AreStatelessResetTokensEqual(
+               token, *alternative_path_.stateless_reset_token);
+  }
+  return false;
 }
 
 void QuicConnection::OnAuthenticatedIetfStatelessResetPacket() {

quiche/quic/core/quic_connection_test.cc

diff --git a/quiche/quic/core/quic_connection_test.cc b/quiche/quic/core/quic_connection_test.cc
index d37545c..b79f9fb 100644
--- a/quiche/quic/core/quic_connection_test.cc
+++ b/quiche/quic/core/quic_connection_test.cc
@@ -6737,7 +6737,6 @@
   QuicConfig config;
   QuicConfigPeer::SetReceivedStatelessResetToken(&config,
                                                  kTestStatelessResetToken);
-  SetQuicReloadableFlag(quic_check_alternate_reset_token, true);
   EXPECT_CALL(*send_algorithm_, SetFromConfig(_, _));
   EXPECT_CALL(*send_algorithm_, EnableECT1()).WillOnce(Return(false));
   EXPECT_CALL(*send_algorithm_, EnableECT0()).WillOnce(Return(false));
@@ -6760,7 +6759,6 @@
   if (!VersionIsIetfQuic(connection_.version().transport_version)) {
     return;
   }
-  SetQuicReloadableFlag(quic_check_alternate_reset_token, true);
   PathProbeTestInit(Perspective::IS_CLIENT);
   QuicConfig config;
   QuicConfigPeer::SetReceivedStatelessResetToken(&config,
@@ -12168,7 +12166,6 @@
   if (!VersionIsIetfQuic(connection_.version().transport_version)) {
     return;
   }
-  SetQuicReloadableFlag(quic_check_alternate_reset_token, true);
   PathProbeTestInit(Perspective::IS_CLIENT);
   QuicConfig config;
   QuicConfigPeer::SetReceivedStatelessResetToken(&config,
@@ -13949,7 +13946,6 @@
   if (!version().IsIetfQuic()) {
     return;
   }
-  SetQuicReloadableFlag(quic_check_alternate_reset_token, true);
   connection_.CreateConnectionIdManager();
   connection_.SetDefaultEncryptionLevel(ENCRYPTION_FORWARD_SECURE);
   connection_.OnHandshakeComplete();