Add support of serving SCT on the server side in QUIC, gated by QUIC_VERSION_30.

net/quic/crypto/crypto_handshake.h

 // Copyright (c) 2013 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_CRYPTO_CRYPTO_HANDSHAKE_H_
 #define NET_QUIC_CRYPTO_CRYPTO_HANDSHAKE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 119 matching lines @@
   // are big-endian and the pair is a P-256 public key.
   std::string channel_id;
 
   // Used when generating proof signature when sending server config updates.
   bool x509_ecdsa_supported;
   bool x509_supported;
 
   // Used to generate cert chain when sending server config updates.
   std::string client_common_set_hashes;
   std::string client_cached_cert_hashes;
+
+  // Default to false; set to true if the client indicates that it supports sct
+  // by sending CSCT tag with an empty value in client hello.
+  bool sct_supported_by_client;
 };
 
 struct NET_EXPORT_PRIVATE QuicCryptoProof {
   QuicCryptoProof();
   ~QuicCryptoProof();
 
   std::string signature;
   // QuicCryptoProof does not take ownership of |certs|.
   const std::vector<std::string>* certs;
+  std::string cert_sct;
 };
 
 // QuicCryptoConfig contains common configuration between clients and servers.
 class NET_EXPORT_PRIVATE QuicCryptoConfig {
  public:
   // kInitialLabel is a constant that is used when deriving the initial
   // (non-forward secure) keys for the connection in order to tie the resulting
   // key to this protocol.
   static const char kInitialLabel[];
 
@@ skipping 17 matching lines @@
 
   const CommonCertSets* common_cert_sets;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(QuicCryptoConfig);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CRYPTO_CRYPTO_HANDSHAKE_H_