Cleanup: Remove unneeded forward declarations in chrome/installer.

chrome/installer/util/app_commands.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_APP_COMMANDS_H_
 #define CHROME_INSTALLER_UTIL_APP_COMMANDS_H_
 #pragma once
 
 #include <windows.h>
 
 #include <map>
 #include <string>
 #include <utility>
 
 #include "base/basictypes.h"
 #include "chrome/installer/util/app_command.h"
 
-class WorkItemList;
-
 namespace base {
 namespace win {
 class RegKey;
 }
 }
 
 namespace installer {
 
 // A collection of AppCommand objects.
 class AppCommands {
@@ skipping 36 matching lines @@
 
  protected:
   CommandMap commands_;
 
   DISALLOW_COPY_AND_ASSIGN(AppCommands);
 };
 
 }  // namespace installer
 
 #endif  // CHROME_INSTALLER_UTIL_APP_COMMANDS_H_