Add relevant tags for PCC Congestion control

net/quic/core/crypto/crypto_protocol.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_QUIC_CORE_CRYPTO_CRYPTO_PROTOCOL_H_
 #define NET_QUIC_CORE_CRYPTO_CRYPTO_PROTOCOL_H_
 
 #include <cstddef>
 #include <string>
 
@@ skipping 64 matching lines @@
                                                  // receive window to
                                                  // 512KB. (2^9 KB).
 const QuicTag kIFWA = TAG('I', 'F', 'W', 'a');   // Set initial size
                                                  // of stream flow control
                                                  // receive window to
                                                  // 1MB. (2^0xa KB).
 const QuicTag kTBBR = TAG('T', 'B', 'B', 'R');   // Reduced Buffer Bloat TCP
 const QuicTag k1RTT = TAG('1', 'R', 'T', 'T');   // STARTUP in BBR for 1 RTT
 const QuicTag k2RTT = TAG('2', 'R', 'T', 'T');   // STARTUP in BBR for 2 RTTs
 const QuicTag kRENO = TAG('R', 'E', 'N', 'O');   // Reno Congestion Control
+const QuicTag kTPCC = TAG('P', 'C', 'C', '\0');  // Performance-Oriented
+                                                 // Congestion Control
 const QuicTag kBYTE = TAG('B', 'Y', 'T', 'E');   // TCP cubic or reno in bytes
 const QuicTag kRATE = TAG('R', 'A', 'T', 'E');   // TCP cubic rate based sending
 const QuicTag kIW03 = TAG('I', 'W', '0', '3');   // Force ICWND to 3
 const QuicTag kIW10 = TAG('I', 'W', '1', '0');   // Force ICWND to 10
 const QuicTag kIW20 = TAG('I', 'W', '2', '0');   // Force ICWND to 20
 const QuicTag kIW50 = TAG('I', 'W', '5', '0');   // Force ICWND to 50
 const QuicTag k1CON = TAG('1', 'C', 'O', 'N');   // Emulate a single connection
 const QuicTag kNTLP = TAG('N', 'T', 'L', 'P');   // No tail loss probe
 const QuicTag kNCON = TAG('N', 'C', 'O', 'N');   // N Connection Congestion Ctrl
 const QuicTag kNRTO = TAG('N', 'R', 'T', 'O');   // CWND reduction on loss
@@ skipping 173 matching lines @@
 // amplification factor of any mirror DoS attack.
 //
 // A client may pad an inchoate client hello to a size larger than
 // kClientHelloMinimumSize to make it more likely to receive a complete
 // rejection message.
 const size_t kClientHelloMinimumSize = 1024;
 
 }  // namespace net
 
 #endif  // NET_QUIC_CORE_CRYPTO_CRYPTO_PROTOCOL_H_