Add support for --critical-update-version to installer.

chrome/installer/util/util_constants.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.
 //
 // Defines all install related constants that need to be used by Chrome as
 // well as Chrome Installer.
 
 #ifndef CHROME_INSTALLER_UTIL_UTIL_CONSTANTS_H_
 #define CHROME_INSTALLER_UTIL_UTIL_CONSTANTS_H_
 #pragma once
@@ skipping 110 matching lines @@
 extern const char kCeee[];
 extern const char kChrome[];
 extern const char kChromeFrame[];
 extern const char kChromeFrameQuickEnable[];
 extern const char kChromeFrameReadyMode[];
 extern const char kChromeFrameReadyModeOptIn[];
 extern const char kChromeFrameReadyModeTempOptOut[];
 extern const char kChromeFrameReadyModeEndTempOptOut[];
 extern const char kChromeSxS[];
 extern const char kCreateAllShortcuts[];
+extern const char kCriticalUpdateVersion[];
 extern const char kDeleteProfile[];
 extern const char kDisableLogging[];
 extern const char kDoNotCreateShortcuts[];
 extern const char kDoNotLaunchChrome[];
 extern const char kDoNotRegisterForUpdateLaunch[];
 extern const char kDoNotRemoveSharedItems[];
 extern const char kEnableLogging[];
 extern const char kForceUninstall[];
 extern const char kInstallArchive[];
 extern const char kInstallerData[];
@@ skipping 55 matching lines @@
 // Google Update named environment variable that implies kSystemLevel.
 extern const char kGoogleUpdateIsMachineEnvVar[];
 
 // Product options.
 extern const wchar_t kOptionMultiInstall[];
 extern const wchar_t kOptionReadyMode[];
 
 }  // namespace installer
 
 #endif  // CHROME_INSTALLER_UTIL_UTIL_CONSTANTS_H_