gfe-relnote: In QUIC, add uber_received_packet_manager which purely wraps a received_packet_manager. Using it is protected by gfe2_reloadable_flag_quic_use_uber_received_packet_manager.

PiperOrigin-RevId: 239601171
Change-Id: Iaa62e2641e0466a03981a6ba7dd128990b09744c
diff --git a/quic/core/quic_received_packet_manager.cc b/quic/core/quic_received_packet_manager.cc
index 921c674..82984eb 100644
--- a/quic/core/quic_received_packet_manager.cc
+++ b/quic/core/quic_received_packet_manager.cc
@@ -154,7 +154,7 @@
 }
 
 bool QuicReceivedPacketManager::IsAwaitingPacket(
-    QuicPacketNumber packet_number) {
+    QuicPacketNumber packet_number) const {
   return quic::IsAwaitingPacket(ack_frame_, packet_number,
                                 peer_least_packet_awaiting_ack_);
 }