Deprecate --gfe2_reloadable_flag_quic_update_ack_alarm_in_send_all_pending_acks.

PiperOrigin-RevId: 319778356
Change-Id: I5a9c03b98f947a0cb0cd32a07019622c5b99c7c6

quic/core/quic_connection.cc

diff --git a/quic/core/quic_connection.cc b/quic/core/quic_connection.cc
index a979139..3263eb9 100644
--- a/quic/core/quic_connection.cc
+++ b/quic/core/quic_connection.cc
@@ -4298,13 +4298,7 @@
       uber_received_packet_manager_.GetEarliestAckTimeout();
   if (timeout.IsInitialized()) {
     // If there are ACKs pending, re-arm ack alarm.
-    if (update_ack_alarm_in_send_all_pending_acks_) {
-      QUIC_RELOADABLE_FLAG_COUNT(
-          quic_update_ack_alarm_in_send_all_pending_acks);
-      ack_alarm_->Update(timeout, kAlarmGranularity);
-    } else {
-      ack_alarm_->Set(timeout);
-    }
+    ack_alarm_->Update(timeout, kAlarmGranularity);
   }
   // Only try to bundle retransmittable data with ACK frame if default
   // encryption level is forward secure.

quic/core/quic_connection.h

diff --git a/quic/core/quic_connection.h b/quic/core/quic_connection.h
index b6bbc38..573cc07 100644
--- a/quic/core/quic_connection.h
+++ b/quic/core/quic_connection.h
@@ -1670,9 +1670,6 @@
   // True if this connection supports handshake done frame.
   bool support_handshake_done_;
 
-  const bool update_ack_alarm_in_send_all_pending_acks_ =
-      GetQuicReloadableFlag(quic_update_ack_alarm_in_send_all_pending_acks);
-
   const bool move_amplification_limit_ =
       GetQuicReloadableFlag(quic_move_amplification_limit);