[Extensions] Code cleanup - const &s

extensions/browser/api/system_network/system_network_api.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 "extensions/browser/api/system_network/system_network_api.h"
 
 namespace {
 const char kNetworkListError[] = "Network lookup failed or unsupported";
 }  // namespace
 
@@ skipping 44 matching lines @@
   error_ = kNetworkListError;
   SendResponse(false);
 }
 
 void SystemNetworkGetNetworkInterfacesFunction::SendResponseOnUIThread(
     const net::NetworkInterfaceList& interface_list) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   std::vector<api::system_network::NetworkInterface> create_arg;
   create_arg.reserve(interface_list.size());
-  for (const net::NetworkInterface interface : interface_list) {
+  for (const net::NetworkInterface& interface : interface_list) {
     api::system_network::NetworkInterface info;
     info.name = interface.name;
     info.address = interface.address.ToString();
     info.prefix_length = interface.prefix_length;
     create_arg.push_back(std::move(info));
   }
 
   results_ =
       api::system_network::GetNetworkInterfaces::Results::Create(create_arg);
   SendResponse(true);
 }
 
 }  // namespace api
 }  // namespace extensions