Always build a QuicSecureConfigUpdater at startup.

net/quic/crypto/quic_crypto_server_config.cc

Index: net/quic/crypto/quic_crypto_server_config.cc
diff --git a/net/quic/crypto/quic_crypto_server_config.cc b/net/quic/crypto/quic_crypto_server_config.cc
index 557435d108562a8519cf20ba4b9346a6e05b4a6a..5440cc697ab20d773c74ea2cd699f248e02fba30 100644
--- a/net/quic/crypto/quic_crypto_server_config.cc
+++ b/net/quic/crypto/quic_crypto_server_config.cc
@@ -1466,6 +1466,11 @@ bool QuicCryptoServerConfig::HasProofSource() const {
   return proof_source_ != nullptr;
 }
 
+int QuicCryptoServerConfig::NumberOfConfigs() const {
+  base::AutoLock locked(configs_lock_);
+  return configs_.size();
+}
+
 HandshakeFailureReason QuicCryptoServerConfig::ParseSourceAddressToken(
     const Config& config,
     StringPiece token,