Get rid of unnecessary forward declarations in components/autofill/

components/autofill/core/browser/credit_card.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_CREDIT_CARD_H_
 #define COMPONENTS_AUTOFILL_CORE_BROWSER_CREDIT_CARD_H_
 
 #include <iosfwd>
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/strings/string16.h"
 #include "components/autofill/core/browser/autofill_data_model.h"
 
 namespace autofill {
 
-struct FormFieldData;
-
 // A form group that stores credit card information.
 class CreditCard : public AutofillDataModel {
  public:
   CreditCard(const std::string& guid, const std::string& origin);
 
   // For use in STL containers.
   CreditCard();
   CreditCard(const CreditCard& credit_card);
   virtual ~CreditCard();
 
@@ skipping 129 matching lines @@
 extern const char* const kDiscoverCard;
 extern const char* const kGenericCard;
 extern const char* const kJCBCard;
 extern const char* const kMasterCard;
 extern const char* const kUnionPay;
 extern const char* const kVisaCard;
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_BROWSER_CREDIT_CARD_H_