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

chrome/installer/util/util_constants.cc

Index: chrome/installer/util/util_constants.cc
diff --git a/chrome/installer/util/util_constants.cc b/chrome/installer/util/util_constants.cc
index 47c3605929bde05ce1befcf943da555c28163002..ef2b07611e16b26f3713b35e99cc7236f840ee89 100644
--- a/chrome/installer/util/util_constants.cc
+++ b/chrome/installer/util/util_constants.cc
@@ -193,6 +193,16 @@ const char kToastResultsKey[] = "toast-results-key";
 
 }  // namespace switches
 
+// The Active Setup executable will be an identical copy of setup.exe; this is
+// necessary because Windows' installer detection heuristics (which include
+// things like process name being "setup.exe") will otherwise force elevation
+// for non-admin users when setup.exe is launched. This is mitigated by adding
+// requestedExecutionLevel="asInvoker" to setup.exe's manifest on Vista+, but
+// there is no such manifest entry on Windows XP (which results in
+// crbug.com/166473).
+// TODO(gab): Rename setup.exe itself altogether and use the same binary for
+// Active Setup.
+const wchar_t kActiveSetupExe[] = L"chrmstp.exe";
 const wchar_t kChromeAppHostExe[] = L"app_host.exe";
 const wchar_t kChromeDll[] = L"chrome.dll";
 const wchar_t kChromeExe[] = L"chrome.exe";