[Autofill] Update the autocomplete types implementation to match the current HTML spec.

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_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/string16.h"
 #include "chrome/browser/autofill/field_types.h"
 #include "chrome/common/form_field_data.h"
 
 class AutofillField : public FormFieldData {
  public:
   enum PhonePart {
     IGNORED = 0,
     PHONE_PREFIX = 1,
     PHONE_SUFFIX = 2,
   };
 
   AutofillField();
   AutofillField(const FormFieldData& field, const string16& unique_name);
   virtual ~AutofillField();
 
   const string16& unique_name() const { return unique_name_; }
 
-  const string16& section() const { return section_; }
+  const std::string& section() const { return section_; }
   AutofillFieldType heuristic_type() const { return heuristic_type_; }
   AutofillFieldType server_type() const { return server_type_; }
   const FieldTypeSet& possible_types() const { return possible_types_; }
   PhonePart phone_part() const { return phone_part_; }
 
   // Sets the heuristic type of this field, validating the input.
-  void set_section(const string16& section) { section_ = section; }
+  void set_section(const std::string& section) { section_ = section; }
   void set_heuristic_type(AutofillFieldType type);
   void set_server_type(AutofillFieldType type);
   void set_possible_types(const FieldTypeSet& possible_types) {
     possible_types_ = possible_types;
   }
   void set_phone_part(PhonePart part) { phone_part_ = part; }
 
   // 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;
 
   // The unique signature of this field, composed of the field name and the html
   // input type in a 32-bit hash.
   std::string FieldSignature() const;
 
   // Returns true if the field type has been determined (without the text in the
   // field).
   bool IsFieldFillable() const;
 
  private:
   // The unique name of this field, generated by Autofill.
   string16 unique_name_;
 
   // The unique identifier for the section (e.g. billing vs. shipping address)
   // that this field belongs to.
-  string16 section_;
+  std::string section_;
 
   // The type of the field, as determined by the Autofill server.
   AutofillFieldType server_type_;
 
   // 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_;
 
   // Used to track whether this field is a phone prefix or suffix.
   PhonePart phone_part_;
 
   DISALLOW_COPY_AND_ASSIGN(AutofillField);
 };
 
 #endif  // CHROME_BROWSER_AUTOFILL_AUTOFILL_FIELD_H_