Deprecate --gfe2_reloadable_flag_quic_delete_config.

The flag gets flipped its default value in cr/921472631 on May 26, which should be released to all binary using this flag.

PiperOrigin-RevId: 954446428

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 b3a6bc6..081def9 100755
--- a/quiche/common/quiche_feature_flags_list.h
+++ b/quiche/common/quiche_feature_flags_list.h
@@ -25,7 +25,6 @@
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_default_enable_5rto_blackhole_detection2, true, true, "If true, default-enable 5RTO blachole detection.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_default_to_bbr, true, false, "When true, defaults to BBR congestion control instead of Cubic.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_default_to_bbr_v2, false, false, "If true, use BBRv2 as the default congestion controller. Takes precedence over --quic_default_to_bbr.")
-QUICHE_FLAG(bool, quiche_reloadable_flag_quic_delete_config, true, true, "If true, the QuicSession will delete the QuicConfig after the handshake completes.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_deliver_stop_sending_to_zombie_streams, true, true, "If true, deliver STOP_SENDING to zombie streams.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_disable_batch_write, false, false, "If true, round-robin stream writes instead of batching in QuicWriteBlockedList.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_disable_server_blackhole_detection, false, false, "If true, disable blackhole detection on server side.")

quiche/quic/core/quic_session.cc

diff --git a/quiche/quic/core/quic_session.cc b/quiche/quic/core/quic_session.cc
index 1157541..9d6d245 100644
--- a/quiche/quic/core/quic_session.cc
+++ b/quiche/quic/core/quic_session.cc
@@ -104,7 +104,6 @@
 
 void QuicSession::SavedConfig::DeleteConfig(ParsedQuicVersion version) {
   if (!delete_config_) {
-    config_deleted_ = true;
     return;
   }
 
@@ -151,7 +150,6 @@
   received_max_bidirectional_streams_ =
       config_->ReceivedMaxBidirectionalStreams();
   idle_network_timeout_ = config_->IdleNetworkTimeout();
-  QUICHE_RELOADABLE_FLAG_COUNT(quic_delete_config);
   config_.reset();
 }
 

quiche/quic/core/quic_session.h

diff --git a/quiche/quic/core/quic_session.h b/quiche/quic/core/quic_session.h
index 38d1fd9..839638d 100644
--- a/quiche/quic/core/quic_session.h
+++ b/quiche/quic/core/quic_session.h
@@ -124,7 +124,6 @@
     // Returns the underlying `QuicConfig`. Must not be called after the config
     // is deleted.
     QuicConfig* RawConfig() {
-      QUIC_BUG_IF(no_config, config_deleted_);
       QUIC_BUG_IF(no_config, delete_config_ && config_ == nullptr);
       return config_.get();
     }
@@ -244,9 +243,7 @@
 
    private:
     std::unique_ptr<QuicConfig> config_;
-    // TODO(b/461482627): Delete this when retiring the flag.
-    bool config_deleted_ = false;
-    bool delete_config_ = GetQuicReloadableFlag(quic_delete_config);
+    bool delete_config_ = true;
 
     bool has_received_initial_stream_flow_control_window_bytes_ = false;
     bool has_received_initial_max_stream_data_bytes_unidirectional_ = false;