Add best-effort/allow rollback flags on WorkItem.

chrome/installer/util/create_reg_key_work_item.h

 // Copyright (c) 2009 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_CREATE_REG_KEY_WORK_ITEM_H__
 #define CHROME_INSTALLER_UTIL_CREATE_REG_KEY_WORK_ITEM_H__
 
 #include <windows.h>
 
 #include <string>
 #include <vector>
 
 #include "chrome/installer/util/work_item.h"
 
 // A WorkItem subclass that creates a registry key at the given path.
 // It also creates all necessary intermediate keys if they do not exist.
 class CreateRegKeyWorkItem : public WorkItem {
  public:
   ~CreateRegKeyWorkItem() override;
 
-  bool Do() override;
-
-  void Rollback() override;
-
  private:
   friend class WorkItem;
 
   CreateRegKeyWorkItem(HKEY predefined_root,
                        const std::wstring& path,
                        REGSAM wow64_access);
 
+  // WorkItem:
+  bool DoImpl() override;
+  void RollbackImpl() override;
+
   // Initialize key_list_ by adding all paths of keys from predefined_root_
   // to path_. Returns true if key_list_ is non empty.
   bool InitKeyList();
 
   // Root key under which we create the new key. The root key can only be
   // one of the predefined keys on Windows.
   HKEY predefined_root_;
 
   // Path of the key to be created.
   std::wstring path_;
 
   // Whether to force 32-bit or 64-bit view of the target key.
   REGSAM wow64_access_;
 
   // List of paths to all keys that need to be created from predefined_root_
   // to path_.
   std::vector<std::wstring> key_list_;
 
   // Whether any key has been created.
   bool key_created_;
 };
 
 #endif  // CHROME_INSTALLER_UTIL_CREATE_REG_KEY_WORK_ITEM_H__