Add rollback support to DeleteRegKeyWorkItem....

chrome/installer/util/delete_reg_key_work_item.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_INSTALLER_UTIL_DELETE_REG_KEY_WORK_ITEM_H_
 #define CHROME_INSTALLER_UTIL_DELETE_REG_KEY_WORK_ITEM_H_
 #pragma once
 
 #include <windows.h>
 
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/scoped_ptr.h"
 #include "chrome/installer/util/work_item.h"
 
-// A WorkItem subclass that deletes a registry key at the given path.
+// A WorkItem subclass that deletes a registry key at the given path.  Be aware
+// that if failures are not ignored, an in-memory backup is made of the key and
+// its values.  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.

[robertshield, 2011/03/01 16:04:43]

Could simplify the above comment to read:

"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."

since if failures ARE ignored, then rollback isn't going to happen.

[grt (UTC plus 2), 2011/03/01 20:54:02]

Done.

 class DeleteRegKeyWorkItem : public WorkItem {
  public:
   virtual ~DeleteRegKeyWorkItem();
 
   virtual bool Do();
 
   virtual void Rollback();
 
  private:
+  class RegKeyBackup;
   friend class WorkItem;
 
   DeleteRegKeyWorkItem(HKEY predefined_root, const std::wstring& path);
 
   // 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_;
 
-  // Path in the registry that the key is backed up to.
-  std::wstring backup_path_;
+  // Backup of the deleted key.
+  scoped_ptr<RegKeyBackup> backup_;
 
- private:
   DISALLOW_COPY_AND_ASSIGN(DeleteRegKeyWorkItem);
 };
 
 #endif  // CHROME_INSTALLER_UTIL_DELETE_REG_KEY_WORK_ITEM_H_