Support --delete-old-versions in setup.exe.

chrome/installer/util/util_constants.cc

 // 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.
 
 #include "chrome/installer/util/util_constants.h"
 
 namespace installer {
 
 namespace switches {
 
@@ skipping 10 matching lines @@
 // Create shortcuts for this user to point to a system-level install (which
 // must already be installed on the machine). The shortcuts created will
 // match the preferences of the already present system-level install as such
 // this option is not compatible with any other installer options.
 const char kConfigureUserSettings[] = "configure-user-settings";
 
 // The version number of an update containing critical fixes, for which an
 // in-use Chrome should be restarted ASAP.
 const char kCriticalUpdateVersion[] = "critical-update-version";
 
+// Delete files that belong to old versions of Chrome from the install
+// directory.
+const char kDeleteOldVersions[] = "delete-old-versions";
+
 // Delete user profile data. This param is useful only when specified with
 // kUninstall, otherwise it is silently ignored.
 const char kDeleteProfile[] = "delete-profile";
 
 // Disable logging
 const char kDisableLogging[] = "disable-logging";
 
 // Prevent installer from launching Chrome after a successful first install.
 const char kDoNotLaunchChrome[] = "do-not-launch-chrome";
 
@@ skipping 210 matching lines @@
 const wchar_t kChromeChannelStableExplicit[] = L"stable";
 
 const size_t kMaxAppModelIdLength = 64U;
 
 const char kCourgette[] = "courgette";
 const char kBsdiff[] = "bsdiff";
 
 const char kSetupHistogramAllocatorName[] = "SetupMetrics";
 
 }  // namespace installer