Return const by ref instead of value

chrome/browser/ui/ash/system_tray_delegate_chromeos.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 "chrome/browser/ui/ash/system_tray_delegate_chromeos.h"
 
 #include <algorithm>
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 368 matching lines @@
   NOTREACHED();
   return ash::user::LOGGED_IN_NONE;
 }
 
 void SystemTrayDelegateChromeOS::ChangeProfilePicture() {
   content::RecordAction(
       base::UserMetricsAction("OpenChangeProfilePictureDialog"));
   ShowSettingsSubPageForActiveUser(chrome::kChangeProfilePictureSubPage);
 }
 
-const std::string SystemTrayDelegateChromeOS::GetEnterpriseDomain() const {
+const std::string& SystemTrayDelegateChromeOS::GetEnterpriseDomain() const {
   return enterprise_domain_;
 }
 
 const base::string16 SystemTrayDelegateChromeOS::GetEnterpriseMessage() const {
   if (GetEnterpriseDomain().empty())
     return base::string16();
   return l10n_util::GetStringFUTF16(IDS_DEVICE_OWNED_BY_NOTICE,
                                     base::UTF8ToUTF16(GetEnterpriseDomain()));
 }
 
@@ skipping 1017 matching lines @@
   LOG(WARNING) << "SystemTrayDelegateChromeOS::GetChildUserMessage call while "
                << "ENABLE_SUPERVISED_USERS undefined.";
   return base::string16();
 }
 
 ash::SystemTrayDelegate* CreateSystemTrayDelegate() {
   return new SystemTrayDelegateChromeOS();
 }
 
 }  // namespace chromeos