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

chrome/installer/util/installer_state.h

Index: chrome/installer/util/installer_state.h
diff --git a/chrome/installer/util/installer_state.h b/chrome/installer/util/installer_state.h
index 2fb0c0d796ff697abc7efc0f1dc4386541b5db69..b6ddb1540b864395b266a7d80b45d44fdc9496be 100644
--- a/chrome/installer/util/installer_state.h
+++ b/chrome/installer/util/installer_state.h
@@ -205,6 +205,9 @@ class InstallerState {
                             int string_resource_id,
                             const std::wstring* launch_cmd) const;
 
+  // Returns true if this install needs to register an Active Setup command.
+  bool RequiresActiveSetup() const;
+
  protected:
   // Returns true if |file| exists and cannot be opened for exclusive write
   // access.