Add the "virtual" keyword on method overrides that are missing it.

chrome/browser/autofill/credit_card.h

 // Copyright (c) 2010 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_CREDIT_CARD_H_
 #define CHROME_BROWSER_AUTOFILL_CREDIT_CARD_H_
 #pragma once
 
 #include <vector>
 
 #include "base/string16.h"
 #include "chrome/browser/autofill/form_group.h"
 
 // A form group that stores credit card information.
 class CreditCard : public FormGroup {
  public:
   explicit CreditCard(const std::string& guid);
 
   // For use in STL containers.
   CreditCard();
   CreditCard(const CreditCard& credit_card);
   virtual ~CreditCard();
 
   // FormGroup implementation:
-  FormGroup* Clone() const;
+  virtual FormGroup* Clone() const;
   virtual void GetPossibleFieldTypes(const string16& text,
                                      FieldTypeSet* possible_types) const;
   virtual void GetAvailableFieldTypes(FieldTypeSet* available_types) const;
   virtual void FindInfoMatches(const AutoFillType& type,
                                const string16& info,
                                std::vector<string16>* matched_text) const;
   virtual string16 GetFieldText(const AutoFillType& type) const;
   virtual string16 GetPreviewText(const AutoFillType& type) const;
   virtual void SetInfo(const AutoFillType& type, const string16& value);
   virtual const string16 Label() const { return label_; }
@@ skipping 110 matching lines @@
   string16 label_;
 
   // The guid of this credit card.
   std::string guid_;
 };
 
 // So we can compare CreditCards with EXPECT_EQ().
 std::ostream& operator<<(std::ostream& os, const CreditCard& credit_card);
 
 #endif  // CHROME_BROWSER_AUTOFILL_CREDIT_CARD_H_