Delete old files after an update.

chrome/chrome_installer_util.gypi

 # Copyright (c) 2012 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.
 
 {
   'target_defaults': {
     'variables': {
       'installer_util_target': 0,
     },
     'target_conditions': [
@@ skipping 22 matching lines @@
           'installer/util/chromium_binaries_distribution.cc',
           'installer/util/chromium_binaries_distribution.h',
           'installer/util/conditional_work_item_list.cc',
           'installer/util/conditional_work_item_list.h',
           'installer/util/copy_tree_work_item.cc',
           'installer/util/copy_tree_work_item.h',
           'installer/util/create_dir_work_item.cc',
           'installer/util/create_dir_work_item.h',
           'installer/util/create_reg_key_work_item.cc',
           'installer/util/create_reg_key_work_item.h',
+          'installer/util/delete_old_versions.cc',
+          'installer/util/delete_old_versions.h',
           'installer/util/delete_reg_key_work_item.cc',
           'installer/util/delete_reg_key_work_item.h',
           'installer/util/delete_reg_value_work_item.cc',
           'installer/util/delete_reg_value_work_item.h',
           'installer/util/delete_tree_work_item.cc',
           'installer/util/delete_tree_work_item.h',
           'installer/util/duplicate_tree_detector.cc',
           'installer/util/duplicate_tree_detector.h',
           'installer/util/firewall_manager_win.cc',
           'installer/util/firewall_manager_win.h',
@@ skipping 181 matching lines @@
           ],
           'include_dirs': [
             '<(DEPTH)',
           ],
         }
       ],
     }],
 
   ],
 }