Add QuicStrCat.

net/tools/quic/quic_client_bin.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A binary wrapper for QuicClient.
 // Connects to a host using QUIC, sends a request to the provided URL, and
 // displays the response.
 //
 // Some usage examples:
 //
@@ skipping 227 matching lines @@
     int rv = net::SynchronousHostResolver::Resolve(host, &addresses);
     if (rv != net::OK) {
       LOG(ERROR) << "Unable to resolve '" << host
                  << "' : " << net::ErrorToShortString(rv);
       return 1;
     }
     ip_addr =
         net::QuicIpAddress(net::QuicIpAddressImpl(addresses[0].address()));
   }
 
-  string host_port =
-      base::StringPrintf("%s:%d", ip_addr.ToString().c_str(), port);
+  string host_port = net::QuicStrCat(ip_addr.ToString(), ":", port);
   VLOG(1) << "Resolved " << host << " to " << host_port << endl;
 
   // Build the client, and try to connect.
   net::EpollServer epoll_server;
   net::QuicServerId server_id(url.host(), url.EffectiveIntPort(),
                               net::PRIVACY_MODE_DISABLED);
   net::QuicVersionVector versions = net::AllSupportedVersions();
   if (FLAGS_quic_version != -1) {
     versions.clear();
     versions.push_back(static_cast<net::QuicVersion>(FLAGS_quic_version));
@@ skipping 108 matching lines @@
       return 0;
     } else {
       cout << "Request failed (redirect " << response_code << ")." << endl;
       return 1;
     }
   } else {
     cerr << "Request failed (" << response_code << ")." << endl;
     return 1;
   }
 }