Fix system-level detection in the mini_installer.

chrome/installer/mini_installer/configuration.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.
 
 #ifndef CHROME_INSTALLER_MINI_INSTALLER_CONFIGURATION_H_
 #define CHROME_INSTALLER_MINI_INSTALLER_CONFIGURATION_H_
 
 #include <windows.h>
 
 #include "chrome/installer/mini_installer/mini_string.h"
@@ skipping 35 matching lines @@
 
   // Returns true if --chrome is explicitly or implicitly on the command line.
   bool has_chrome() const { return has_chrome_; }
 
   // Returns true if --chrome-frame is on the command line.
   bool has_chrome_frame() const { return has_chrome_frame_; }
 
   // Returns true if --multi-install is on the command line.
   bool is_multi_install() const { return is_multi_install_; }
 
-  // Returns true if --system-level is on the command line.
+  // Returns true if --system-level is on the command line or if
+  // GoogleUpdateIsMachine=1 is set in the process's environment.
   bool is_system_level() const { return is_system_level_; }
 
   // Retuns true if --chrome-sxs is on the command line.
   bool is_side_by_side() const { return is_side_by_side_; }
 
   // Returns the previous version contained in the image's resource.
   const wchar_t* previous_version() const { return previous_version_; }
 
  protected:
   void Clear();
@@ skipping 23 matching lines @@
  private:
   Configuration(const Configuration&);
   Configuration& operator=(const Configuration&);
 
   void SetChromeAppGuid();
 };
 
 }  // namespace mini_installer
 
 #endif  // CHROME_INSTALLER_MINI_INSTALLER_CONFIGURATION_H_