Deprecate --gfe2_reloadable_flag_quic_dont_defer_sending.

PiperOrigin-RevId: 363180200
Change-Id: Ib94666a8db01ec6c5b17e24dc4f09450900e1672

quic/core/quic_connection.cc

diff --git a/quic/core/quic_connection.cc b/quic/core/quic_connection.cc
index fd3955e..66821ef 100644
--- a/quic/core/quic_connection.cc
+++ b/quic/core/quic_connection.cc
@@ -699,9 +699,7 @@
   if (config.HasClientSentConnectionOption(kEACK, perspective_)) {
     bundle_retransmittable_with_pto_ack_ = true;
   }
-  if (GetQuicReloadableFlag(quic_dont_defer_sending) &&
-      config.HasClientSentConnectionOption(kDFER, perspective_)) {
-    QUIC_RELOADABLE_FLAG_COUNT(quic_dont_defer_sending);
+  if (config.HasClientSentConnectionOption(kDFER, perspective_)) {
     defer_send_in_response_to_packets_ = false;
   }
   if (config.HasReceivedMaxPacketSize()) {

quic/core/quic_flags_list.h

diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index 55fa033..a4f0cca 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -34,7 +34,6 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_discard_initial_packet_with_key_dropped, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_do_not_synthesize_source_cid_for_short_header, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_donot_reset_ideal_next_packet_send_time, false)
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_dont_defer_sending, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_enable_alps_client, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_enable_alps_server, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_enable_mtu_discovery_at_server, false)