C++ Readability for grt.

chrome/installer/util/registry_key_backup.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_REGISTRY_KEY_BACKUP_H_
 #define CHROME_INSTALLER_UTIL_REGISTRY_KEY_BACKUP_H_
 #pragma once
 
 #include <windows.h>
 
@@ skipping 31 matching lines @@
   // initialized from a non-existent key.
   bool WriteTo(HKEY root, const wchar_t* key_path) const;
 
   void swap(RegistryKeyBackup& other) {
     key_data_.swap(other.key_data_);
   }
 
  private:
   class KeyData;
 
+  // The values and subkeys of the backed-up key.
   scoped_ptr<KeyData> key_data_;
 
   DISALLOW_COPY_AND_ASSIGN(RegistryKeyBackup);
 };
 
 #endif  // CHROME_INSTALLER_UTIL_REGISTRY_KEY_BACKUP_H_