Deprecate --gfe2_reloadable_flag_quic_allow_flow_label_blackhole_avoidance_on_server.

PiperOrigin-RevId: 826285193

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 ee1f0e1..172ea24 100755
--- a/quiche/common/quiche_feature_flags_list.h
+++ b/quiche/common/quiche_feature_flags_list.h
@@ -13,7 +13,6 @@
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_add_stream_info_to_idle_close_detail, false, true, "If true, include stream information in idle timeout connection close detail.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_allow_client_enabled_2x_initial_cwnd, true, true, "Doubles the initial congestion window for QUIC connections when initiated by the client")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_allow_client_enabled_bbr_v2, true, true, "If true, allow client to enable BBRv2 on server via connection option 'B2ON'.")
-QUICHE_FLAG(bool, quiche_reloadable_flag_quic_allow_flow_label_blackhole_avoidance_on_server, true, true, "Change the flow label on the server side and attempt repathing to avoid blackhole.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_bbr2_extra_acked_window, false, true, "When true, the BBR4 copt sets the extra_acked window to 20 RTTs and BBR5 sets it to 40 RTTs.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_bbr2_probe_two_rounds, true, true, "When true, the BB2U copt causes BBR2 to wait two rounds with out draining the queue before exiting PROBE_UP and BB2S has the same effect in STARTUP.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_bbr2_simplify_inflight_hi, true, true, "When true, the BBHI copt causes QUIC BBRv2 to use a simpler algorithm for raising inflight_hi in PROBE_UP.")

quiche/quic/core/http/end_to_end_test.cc

diff --git a/quiche/quic/core/http/end_to_end_test.cc b/quiche/quic/core/http/end_to_end_test.cc
index 4dcca8f..3b0be31 100644
--- a/quiche/quic/core/http/end_to_end_test.cc
+++ b/quiche/quic/core/http/end_to_end_test.cc
@@ -8748,8 +8748,6 @@
 }
 
 TEST_P(EndToEndTest, ChangeFlowLabelOnRTO) {
-  SetQuicReloadableFlag(quic_allow_flow_label_blackhole_avoidance_on_server,
-                        true);
   client_extra_copts_.push_back(kCFLS);
   server_address_ =
       QuicSocketAddress(QuicIpAddress::Loopback6(), server_address_.port());

quiche/quic/core/quic_connection.cc

diff --git a/quiche/quic/core/quic_connection.cc b/quiche/quic/core/quic_connection.cc
index 1507ed9..38922fa 100644
--- a/quiche/quic/core/quic_connection.cc
+++ b/quiche/quic/core/quic_connection.cc
@@ -625,11 +625,7 @@
   }
 
   if (perspective_ == Perspective::IS_SERVER && version().HasIetfQuicFrames() &&
-      config.HasClientSentConnectionOption(kCFLS, perspective_) &&
-      GetQuicReloadableFlag(
-          quic_allow_flow_label_blackhole_avoidance_on_server)) {
-    QUIC_RELOADABLE_FLAG_COUNT(
-        quic_allow_flow_label_blackhole_avoidance_on_server);
+      config.HasClientSentConnectionOption(kCFLS, perspective_)) {
     EnableBlackholeAvoidanceViaFlowLabel();
   }