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

net/dns/mdns_client_unittest.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 <queue>
 
 #include "base/location.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 394 matching lines @@
     Save(value);
   }
 
   void Save(const RecordParsed* value) {
     set_ = true;
     name_ = value->name();
     ptrdomain_ = value->rdata<PtrRecordRdata>()->ptrdomain();
     ttl_ = value->ttl();
   }
 
-  bool IsRecordWith(std::string name, std::string ptrdomain) {
+  bool IsRecordWith(const std::string& name, const std::string& ptrdomain) {
     return set_ && name_ == name && ptrdomain_ == ptrdomain;
   }
 
   const std::string& name() { return name_; }
   const std::string& ptrdomain() { return ptrdomain_; }
   int ttl() { return ttl_; }
 
  private:
   bool set_;
   std::string name_;
@@ skipping 888 matching lines @@
               SendToInternal(sample_packet_, "224.0.0.251:5353", _))
       .Times(0);
   // Expect call for the second IPv6 packed.
   EXPECT_CALL(*socket_ipv6_,
               SendToInternal(sample_packet_, "[ff02::fb]:5353", _))
       .WillOnce(Return(OK));
   callback.Run(OK);
 }
 
 }  // namespace net