If Chrome Binaries version > App Host version, then update App Host.

chrome/chrome_browser_extensions.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.
 
 {
   'targets': [
     {
       'target_name': 'browser_extensions',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 790 matching lines @@
             ],
           },
           'dependencies': [
             '<(DEPTH)/base/base.gyp:base',
             '<(DEPTH)/chrome/chrome.gyp:launcher_support',
             '<(DEPTH)/google_update/google_update.gyp:google_update',
           ],
           'sources': [
             'browser/extensions/app_host/app_host.rc',
             'browser/extensions/app_host/app_host_main.cc',
+            'browser/extensions/app_host/app_host_upgrade.cc',
+            'browser/extensions/app_host/app_host_upgrade.h',
             'browser/extensions/app_host/binaries_installer.cc',
             'browser/extensions/app_host/binaries_installer.h',
             'browser/extensions/app_host/binaries_installer_internal.cc',
             'browser/extensions/app_host/binaries_installer_internal.h',
           ],
         },
       ],
     }, ],  # 'OS=="win"'
   ],  # 'conditions'
 }