Deprecate gfe2_reloadable_flag_quic_ignore_peer_max_ack_delay_during_handshake.

PiperOrigin-RevId: 428864648

quic/core/quic_flags_list.h

diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index 069ba10..4e7be52 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -79,8 +79,6 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_flush_pending_frames_and_padding_bytes_on_migration, true)
 // If true, ietf connection migration is no longer conditioned on connection option RVCM.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_remove_connection_migration_connection_option, false)
-// If true, ignore peer_max_ack_delay during handshake.
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_ignore_peer_max_ack_delay_during_handshake, true)
 // If true, include stream information in idle timeout connection close detail.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_add_stream_info_to_idle_close_detail, true)
 // If true, pass the received PATH_RESPONSE payload to path validator to move forward the path validation.

quic/core/quic_sent_packet_manager.cc

diff --git a/quic/core/quic_sent_packet_manager.cc b/quic/core/quic_sent_packet_manager.cc
index 55dbe05..af86d2f 100644
--- a/quic/core/quic_sent_packet_manager.cc
+++ b/quic/core/quic_sent_packet_manager.cc
@@ -1537,12 +1537,9 @@
                                             QuicTime ack_receive_time) {
   QUICHE_DCHECK(packets_acked_.empty());
   QUICHE_DCHECK_LE(largest_acked, unacked_packets_.largest_sent_packet());
-  if (GetQuicReloadableFlag(quic_ignore_peer_max_ack_delay_during_handshake) &&
-      supports_multiple_packet_number_spaces() && !handshake_finished_) {
-    QUIC_RELOADABLE_FLAG_COUNT(quic_ignore_peer_max_ack_delay_during_handshake);
-    // Ignore peer_max_ack_delay and use received ack_delay during
-    // handshake.
-  } else {
+  // Ignore peer_max_ack_delay and use received ack_delay during
+  // handshake when supporting multiple packet number spaces.
+  if (!supports_multiple_packet_number_spaces() || handshake_finished_) {
     if (ack_delay_time > peer_max_ack_delay()) {
       ack_delay_time = peer_max_ack_delay();
     }

quic/core/quic_sent_packet_manager_test.cc

diff --git a/quic/core/quic_sent_packet_manager_test.cc b/quic/core/quic_sent_packet_manager_test.cc
index 1ce3da8..8b4ceac 100644
--- a/quic/core/quic_sent_packet_manager_test.cc
+++ b/quic/core/quic_sent_packet_manager_test.cc
@@ -4596,14 +4596,7 @@
   EXPECT_EQ(PACKETS_NEWLY_ACKED,
             manager_.OnAckFrameEnd(clock_.Now(), QuicPacketNumber(2),
                                    ENCRYPTION_HANDSHAKE));
-  if (GetQuicReloadableFlag(quic_ignore_peer_max_ack_delay_during_handshake)) {
-    EXPECT_EQ(kTestRTT, manager_.GetRttStats()->latest_rtt());
-  } else {
-    // Verify the ack_delay gets capped by the peer_max_ack_delay.
-    EXPECT_EQ(kTestRTT + queuing_delay -
-                  QuicTime::Delta::FromMilliseconds(kDefaultDelayedAckTimeMs),
-              manager_.GetRttStats()->latest_rtt());
-  }
+  EXPECT_EQ(kTestRTT, manager_.GetRttStats()->latest_rtt());
 }
 
 TEST_F(QuicSentPacketManagerTest, BuildAckFrequencyFrameWithSRTT) {