Introduce a SetRegValueWorkItem overload that accepts a callback instead (...)

chrome/installer/util/set_reg_value_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_SET_REG_VALUE_WORK_ITEM_H__
 #define CHROME_INSTALLER_UTIL_SET_REG_VALUE_WORK_ITEM_H__
 
 #include <windows.h>
 
 #include <string>
 #include <vector>
 
+#include "base/callback.h"
 #include "chrome/installer/util/work_item.h"
 
 // A WorkItem subclass that sets a registry value with REG_SZ, REG_DWORD, or
 // REG_QWORD type at the specified path. The value is only set if the target key
 // exists.
 class SetRegValueWorkItem : public WorkItem {
  public:
   ~SetRegValueWorkItem() override;
 
   bool Do() override;
@@ skipping 33 matching lines @@
                       DWORD value_data,
                       bool overwrite);
 
   SetRegValueWorkItem(HKEY predefined_root,
                       const std::wstring& key_path,
                       REGSAM wow64_access,
                       const std::wstring& value_name,
                       int64 value_data,
                       bool overwrite);
 
+  // Implies |overwrite_| and TYPE_SZ for now.
+  SetRegValueWorkItem(HKEY predefined_root,
+                      const std::wstring& key_path,
+                      REGSAM wow64_access,
+                      const std::wstring& value_name,
+                      const GetValueFromExistingCallback& get_value_callback);
+
   // Root key of the target key under which the value is set. The root key can
   // only be one of the predefined keys on Windows.
   HKEY predefined_root_;
 
   // Path of the target key under which the value is set.
   std::wstring key_path_;
 
   // Name of the value to be set.
   std::wstring value_name_;
 
+  // If this is set, it will be used to get the desired value to be set based on
+  // the existing value in the registry.
+  const GetValueFromExistingCallback get_value_callback_;
+
   // Whether to overwrite the existing value under the target key.
   bool overwrite_;
 
   // Whether to force 32-bit or 64-bit view of the target key.
   REGSAM wow64_access_;
 
   // Type of data to store
   DWORD type_;
   std::vector<uint8> value_;
   DWORD previous_type_;
   std::vector<uint8> previous_value_;
 
   SettingStatus status_;
 };
 
 #endif  // CHROME_INSTALLER_UTIL_SET_REG_VALUE_WORK_ITEM_H__