Cleanup return values in autofill

components/autofill/core/browser/autofill_profile.h

 // 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.
 
 #ifndef COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_PROFILE_H_
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_PROFILE_H_
 
 #include <stddef.h>
 
 #include <iosfwd>
@@ skipping 81 matching lines @@
   bool EqualsSansGuid(const AutofillProfile& profile) const;
 
   // Equality operators compare GUIDs, origins, language code, and the contents
   // in the comparison.
   bool operator==(const AutofillProfile& profile) const;
   virtual bool operator!=(const AutofillProfile& profile) const;
 
   // Returns concatenation of full name and address line 1.  This acts as the
   // basis of comparison for new values that are submitted through forms to
   // aid with correct aggregation of new data.
-  const base::string16 PrimaryValue() const;
+  const base::string16& PrimaryValue() const;
 
   // Returns true if the data in this AutofillProfile is a subset of the data in
   // |profile|.
   bool IsSubsetOf(const AutofillProfile& profile,
                   const std::string& app_locale) const;
 
   // Overwrites the single-valued field data in |profile| with this
   // Profile.  Or, for multi-valued fields append the new values.
   void OverwriteWithOrAddTo(const AutofillProfile& profile,
                             const std::string& app_locale);
@@ skipping 94 matching lines @@
   // The BCP 47 language code that can be used to format |address_| for display.
   std::string language_code_;
 };
 
 // So we can compare AutofillProfiles with EXPECT_EQ().
 std::ostream& operator<<(std::ostream& os, const AutofillProfile& profile);
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_AUTOFILL_PROFILE_H_