Update from https://crrev.com/303153

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 a5c5d08cfc24e6bb4ea2653cb0e1e5c4d6ae0f77..5a650b6073035455723effdc2cc353d17b806e5b 100644
--- a/net/quic/crypto/quic_crypto_server_config.cc
+++ b/net/quic/crypto/quic_crypto_server_config.cc
@@ -1420,6 +1420,10 @@ string QuicCryptoServerConfig::NewSourceAddressToken(
       rand, source_address_token.SerializeAsString());
 }
 
+bool QuicCryptoServerConfig::HasProofSource() const {
+  return proof_source_ != nullptr;
+}
+
 HandshakeFailureReason QuicCryptoServerConfig::ValidateSourceAddressToken(
     const Config& config,
     StringPiece token,