Duplicate setup.exe into an identical executable and point Active Setup to that executable instead.

chrome/installer/util/util_constants.h

 // 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.
 //
 // 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_
 
@@ skipping 160 matching lines @@
 extern const char kUpdateSetupExe[];
 extern const char kVerboseLogging[];
 extern const char kShowEula[];
 extern const char kShowEulaForMetro[];
 extern const char kInactiveUserToast[];
 extern const char kSystemLevelToast[];
 extern const char kExperimentGroup[];
 extern const char kToastResultsKey[];
 }  // namespace switches
 
+extern const wchar_t kActiveSetupExe[];
 extern const wchar_t kChromeAppHostExe[];
 extern const wchar_t kChromeDll[];
 extern const wchar_t kChromeExe[];
 extern const wchar_t kChromeFrameDll[];
 extern const wchar_t kChromeFrameHelperExe[];
 extern const wchar_t kChromeFrameHelperWndClass[];
 extern const wchar_t kChromeFrameReadyModeField[];
 extern const wchar_t kChromeLauncherExe[];
 extern const wchar_t kChromeOldExe[];
 extern const wchar_t kChromeNewExe[];
@@ skipping 42 matching lines @@
 extern const wchar_t kChromeChannelCanary[];
 extern const wchar_t kChromeChannelDev[];
 extern const wchar_t kChromeChannelBeta[];
 extern const wchar_t kChromeChannelStable[];
 
 extern const size_t kMaxAppModelIdLength;
 
 }  // namespace installer
 
 #endif  // CHROME_INSTALLER_UTIL_UTIL_CONSTANTS_H_