Update {virtual,override} to follow C++11 style in chrome.

chrome/installer/util/delete_reg_key_work_item.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_INSTALLER_UTIL_DELETE_REG_KEY_WORK_ITEM_H_
 #define CHROME_INSTALLER_UTIL_DELETE_REG_KEY_WORK_ITEM_H_
 
 #include <windows.h>
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "chrome/installer/util/registry_key_backup.h"
 #include "chrome/installer/util/work_item.h"
 
 class RegistryKeyBackup;
 
 // A WorkItem subclass that deletes a registry key at the given path.  Be aware
 // that in the event of rollback the key's values and subkeys are restored but
 // the key and its subkeys take on their default security descriptors.
 class DeleteRegKeyWorkItem : public WorkItem {
  public:
-  virtual ~DeleteRegKeyWorkItem();
+  ~DeleteRegKeyWorkItem() override;
 
-  virtual bool Do() override;
+  bool Do() override;
 
-  virtual void Rollback() override;
+  void Rollback() override;
 
  private:
   friend class WorkItem;
 
   DeleteRegKeyWorkItem(HKEY predefined_root,
                        const std::wstring& path,
                        REGSAM wow64_access);
 
   // Root key from which we delete the key. The root key can only be
   // one of the predefined keys on Windows.
   HKEY predefined_root_;
 
   // Path of the key to be deleted.
   std::wstring path_;
 
   // Whether to force 32-bit or 64-bit view of the target key.
   REGSAM wow64_access_;
 
   // Backup of the deleted key.
   RegistryKeyBackup backup_;
 
   DISALLOW_COPY_AND_ASSIGN(DeleteRegKeyWorkItem);
 };
 
 #endif  // CHROME_INSTALLER_UTIL_DELETE_REG_KEY_WORK_ITEM_H_