Return const by ref instead of value

chrome/browser/ui/ash/system_tray_delegate_chromeos.h

Index: chrome/browser/ui/ash/system_tray_delegate_chromeos.h
diff --git a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
index c1c193d513726002bd8161ee2a13d668973632a4..2305805145fc2071b1a1240342ead6323d03be9b 100644
--- a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
+++ b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
@@ -79,7 +79,7 @@ class SystemTrayDelegateChromeOS
   bool GetTrayVisibilityOnStartup() override;
   ash::user::LoginStatus GetUserLoginStatus() const override;
   void ChangeProfilePicture() override;
-  const std::string GetEnterpriseDomain() const override;
+  const std::string& GetEnterpriseDomain() const override;

[stevenjb, 2015/09/09 18:10:45]

This shouldn't compile. GetEnterpriseDomain() is is a virtual method that
returns a string. In general, virtual methods shouldn't return references since
a particular implementation might e.g. return a new empty string.

If we actually care about cleaning this up, we should replace 'const string' for
all of these with just 'string' in the ash::SystemTrayDelegate header and all
derived methods.

   const base::string16 GetEnterpriseMessage() const override;
   const std::string GetSupervisedUserManager() const override;
   const base::string16 GetSupervisedUserManagerName() const override;