Slight improvement to QUIC version negotation debug logging.

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index 9289b66701270a411a688cc377b60d73bf2fa875..c08706d8507364fc6ee4575c4bd5b4700b048392 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -409,7 +409,8 @@ void QuicConnection::OnVersionNegotiationPacket(
     return;
   }
 
-  DVLOG(1) << ENDPOINT << "negotiating version " << version();
+  DVLOG(1) << ENDPOINT
+           << "Negotiated version: " << QuicVersionToString(version());
   server_supported_versions_ = packet.versions;
   version_negotiation_state_ = NEGOTIATION_IN_PROGRESS;
   RetransmitUnackedPackets(ALL_PACKETS);
@@ -969,6 +970,8 @@ void QuicConnection::SendVersionNegotiationPacket() {
     visitor_->OnWriteBlocked();
     return;
   }
+  DVLOG(1) << ENDPOINT << "Sending version negotiation packet: {"
+           << QuicVersionVectorToString(framer_.supported_versions()) << "}";
   scoped_ptr<QuicEncryptedPacket> version_packet(
       packet_generator_.SerializeVersionNegotiationPacket(
           framer_.supported_versions()));