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

net/quic/crypto/quic_crypto_server_config.h

Index: net/quic/crypto/quic_crypto_server_config.h
diff --git a/net/quic/crypto/quic_crypto_server_config.h b/net/quic/crypto/quic_crypto_server_config.h
index 02d0523348589ea6c5505079c61f63afdeaddbb8..8f4b38f2e850ff54f06a4a6f9df1e2bb9345667b 100644
--- a/net/quic/crypto/quic_crypto_server_config.h
+++ b/net/quic/crypto/quic_crypto_server_config.h
@@ -271,6 +271,7 @@ class NET_EXPORT_PRIVATE QuicCryptoServerConfig {
   //
   // |cached_network_params| is optional, and can be nullptr.
   bool BuildServerConfigUpdateMessage(
+      QuicVersion version,
       const SourceAddressTokens& previous_source_address_tokens,
       const IPAddressNumber& server_ip,
       const IPAddressNumber& client_ip,
@@ -338,6 +339,10 @@ class NET_EXPORT_PRIVATE QuicCryptoServerConfig {
   // uniqueness.
   void set_server_nonce_strike_register_window_secs(uint32 window_secs);
 
+  // set_enable_serving_sct enables or disables serving signed cert timestamp
+  // (RFC6962) in server hello.
+  void set_enable_serving_sct(bool enable_serving_sct);
+
   // Set and take ownership of the callback to invoke on primary config changes.
   void AcquirePrimaryConfigChangedCb(PrimaryConfigChangedCallback* cb);
 
@@ -438,14 +443,13 @@ class NET_EXPORT_PRIVATE QuicCryptoServerConfig {
       ValidateClientHelloResultCallback* done_cb) const;
 
   // BuildRejection sets |out| to be a REJ message in reply to |client_hello|.
-  void BuildRejection(const Config& config,
+  void BuildRejection(QuicVersion version, const Config& config,
                       const CryptoHandshakeMessage& client_hello,
                       const ClientHelloInfo& info,
                       const CachedNetworkParameters& cached_network_params,
                       bool use_stateless_rejects,
                       QuicConnectionId server_designated_connection_id,
-                      QuicRandom* rand,
-                      QuicCryptoNegotiatedParameters* params,
+                      QuicRandom* rand, QuicCryptoNegotiatedParameters* params,
                       const QuicCryptoProof& crypto_proof,
                       CryptoHandshakeMessage* out) const;
 
@@ -593,6 +597,9 @@ class NET_EXPORT_PRIVATE QuicCryptoServerConfig {
   uint32 server_nonce_strike_register_max_entries_;
   uint32 server_nonce_strike_register_window_secs_;
 
+  // Enable serving SCT or not.
+  bool enable_serving_sct_;
+
   DISALLOW_COPY_AND_ASSIGN(QuicCryptoServerConfig);
 };