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

components/signin/core/common/profile_management_switches.cc

 // Copyright 2014 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 "components/signin/core/common/profile_management_switches.h"
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "build/build_config.h"
 #include "components/signin/core/common/signin_switches.h"
@@ skipping 88 matching lines @@
     } else if (trial_type == "NewAvatarMenu") {
       state = STATE_NEW_AVATAR_MENU;
     } else {
       state = STATE_NEW_PROFILE_MANAGEMENT;
     }
   }
 
   return state;
 }
 
-bool CheckFlag(std::string command_switch, State min_state) {
+bool CheckFlag(const std::string& command_switch, State min_state) {
   // Individiual flag settings take precedence.
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(command_switch))
     return true;
 
   return GetProcessState() >= min_state;
 }
 
 }  // namespace
 
 namespace switches {
@@ skipping 53 matching lines @@
   command_line->AppendSwitch(switches::kEnableNewProfileManagement);
   DCHECK(!command_line->HasSwitch(switches::kDisableNewProfileManagement));
 }
 
 void EnableAccountConsistencyForTesting(base::CommandLine* command_line) {
   command_line->AppendSwitch(switches::kEnableAccountConsistency);
   DCHECK(!command_line->HasSwitch(switches::kDisableAccountConsistency));
 }
 
 }  // namespace switches