Reduce boxing and unboxing of AutofillFieldType

chrome/browser/autofill/autofill_field.h

 // Copyright (c) 2011 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 CHROME_BROWSER_AUTOFILL_AUTOFILL_FIELD_H_
 #define CHROME_BROWSER_AUTOFILL_AUTOFILL_FIELD_H_
 #pragma once
 
 #include <string>
 
 #include "base/string16.h"
 #include "chrome/browser/autofill/field_types.h"
 #include "webkit/glue/form_field.h"
 
 class AutofillField : public webkit_glue::FormField {
  public:
   AutofillField();
   AutofillField(const webkit_glue::FormField& field,
                 const string16& unique_name);
   virtual ~AutofillField();
 
   const string16& unique_name() const { return unique_name_; }
 
   AutofillFieldType heuristic_type() const { return heuristic_type_; }
   AutofillFieldType server_type() const { return server_type_; }
   const FieldTypeSet& possible_types() const { return possible_types_; }
 
   // Sets the heuristic type of this field, validating the input.
-  void set_heuristic_type(const AutofillFieldType& type);
-  void set_server_type(const AutofillFieldType& type) { server_type_ = type; }
+  void set_heuristic_type(AutofillFieldType type);
+  void set_server_type(AutofillFieldType type) { server_type_ = type; }
   void set_possible_types(const FieldTypeSet& possible_types) {
     possible_types_ = possible_types;
   }
 
   // This function automatically chooses between server and heuristic autofill
   // type, depending on the data available.
   AutofillFieldType type() const;
 
   // Returns true if the value of this field is empty.
   bool IsEmpty() const;
@@ skipping 16 matching lines @@
   // The type of the field, as determined by the local heuristics.
   AutofillFieldType heuristic_type_;
 
   // The set of possible types for this field.
   FieldTypeSet possible_types_;
 
   DISALLOW_COPY_AND_ASSIGN(AutofillField);
 };
 
 #endif  // CHROME_BROWSER_AUTOFILL_AUTOFILL_FIELD_H_