Cleanup: Pass std::string as const reference if possible

net/dns/mdns_client_impl.cc

 // Copyright 2013 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.
 
 #include "net/dns/mdns_client_impl.h"
 
 #include <algorithm>
 #include <queue>
 
 #include "base/bind.h"
@@ skipping 194 matching lines @@
 }
 
 MDnsClientImpl::Core::~Core() {
   STLDeleteValues(&listeners_);
 }
 
 bool MDnsClientImpl::Core::Init(MDnsSocketFactory* socket_factory) {
   return connection_->Init(socket_factory);
 }
 
-bool MDnsClientImpl::Core::SendQuery(uint16 rrtype, std::string name) {
+bool MDnsClientImpl::Core::SendQuery(uint16 rrtype, const std::string& name) {
   std::string name_dns;
   if (!DNSDomainFromDot(name, &name_dns))
     return false;
 
   DnsQuery query(0, name_dns, rrtype);
   query.set_flags(0);  // Remove the RD flag from the query. It is unneeded.
 
   connection_->Send(query.io_buffer(), query.io_buffer()->size());
   return true;
 }
@@ skipping 515 matching lines @@
 
 void MDnsTransactionImpl::OnNsecRecord(const std::string& name, unsigned type) {
   TriggerCallback(RESULT_NSEC, NULL);
 }
 
 void MDnsTransactionImpl::OnCachePurged() {
   // TODO(noamsml): Cache purge situations not yet implemented
 }
 
 }  // namespace net