Switch to PacketNumberQueue interval iteration and avoid allocations in new ACK frame generation. G…

net/quic/quic_flags.cc

Index: net/quic/quic_flags.cc
diff --git a/net/quic/quic_flags.cc b/net/quic/quic_flags.cc
index fe7e452b9907a474035e9359592d53932c2877c1..c374f26c15fe925b60d6675dc5cd5e1efe5ed4f7 100644
--- a/net/quic/quic_flags.cc
+++ b/net/quic/quic_flags.cc
@@ -142,3 +142,7 @@ bool FLAGS_quic_change_alarms_efficiently = false;
 // If true, requires handshake confirmations for all QUIC handshakes with
 // versions less than 33.
 bool FLAGS_quic_require_handshake_confirmation_pre33 = false;
+
+// If true, use the interval form of iteration over a PacketNumberQueue instead
+// of iterating over the individual numbers.
+bool FLAGS_quic_use_packet_number_queue_intervals = false;