Fix a few spurious string allocations in QuicCryptoServerStream and QuicCryptoStream. No functional…

net/quic/quic_crypto_server_stream.cc

Index: net/quic/quic_crypto_server_stream.cc
diff --git a/net/quic/quic_crypto_server_stream.cc b/net/quic/quic_crypto_server_stream.cc
index cee73caa62c4918a108b4c7ce58cef1d96549b79..7bbe766803799680268e9dc8206fdf511fd78be0 100644
--- a/net/quic/quic_crypto_server_stream.cc
+++ b/net/quic/quic_crypto_server_stream.cc
@@ -236,7 +236,7 @@ void QuicCryptoServerStream::SendServerConfigUpdate(
   DVLOG(1) << "Server: Sending server config update: "
            << server_config_update_message.DebugString();
   const QuicData& data = server_config_update_message.GetSerialized();
-  WriteOrBufferData(string(data.data(), data.length()), false, nullptr);
+  WriteOrBufferData(StringPiece(data.data(), data.length()), false, nullptr);
 
   ++num_server_config_update_messages_sent_;
 }