Add a new QUIC Ack Decimation mode that is reordering tolerant. Protected by FLAG_quic_ack_decimati…

net/quic/crypto/crypto_protocol.h

Index: net/quic/crypto/crypto_protocol.h
diff --git a/net/quic/crypto/crypto_protocol.h b/net/quic/crypto/crypto_protocol.h
index 5d2f71f57a974b03b8841759bd40511cd01bbdfe..25250bef7cbf1471e2517c9f576a3513cf27a233 100644
--- a/net/quic/crypto/crypto_protocol.h
+++ b/net/quic/crypto/crypto_protocol.h
@@ -89,6 +89,8 @@ const QuicTag kMIN4 = TAG('M', 'I', 'N', '4');   // Min CWND of 4 packets,
 const QuicTag kTLPR = TAG('T', 'L', 'P', 'R');   // Tail loss probe delay of
                                                  // 0.5RTT.
 const QuicTag kACKD = TAG('A', 'C', 'K', 'D');   // Ack decimation style acking.
+const QuicTag kAKD2 = TAG('A', 'K', 'D', '2');   // Ack decimation tolerating
+                                                 // out of order packets.
 const QuicTag kSSLR = TAG('S', 'S', 'L', 'R');   // Slow Start Large Reduction.
 
 // Optional support of truncated Connection IDs.  If sent by a peer, the value