[Autofill] Add the phone extension type.

components/autofill/core/browser/phone_number.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 "components/autofill/core/browser/phone_number.h"
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/autofill/core/browser/autofill_country.h"
@@ skipping 101 matching lines @@
     case PHONE_HOME_CITY_CODE:
       return cached_parsed_phone_.city_code();
 
     case PHONE_HOME_COUNTRY_CODE:
       return cached_parsed_phone_.country_code();
 
     case PHONE_HOME_CITY_AND_NUMBER:
       return
           cached_parsed_phone_.city_code() + cached_parsed_phone_.number();
 
+    case PHONE_HOME_EXTENSION:
+      return base::string16();
+
     default:
       NOTREACHED();
       return base::string16();
   }
 }
 
 bool PhoneNumber::SetInfo(const AutofillType& type,
                           const base::string16& value,
                           const std::string& app_locale) {
   SetRawInfo(type.GetStorableType(), value);
@@ skipping 125 matching lines @@
 
   return i18n::ConstructPhoneNumber(
       country_, city_, phone_, GetRegion(profile, app_locale), value);
 }
 
 bool PhoneNumber::PhoneCombineHelper::IsEmpty() const {
   return phone_.empty() && whole_number_.empty();
 }
 
 }  // namespace autofill