Add installer::SetupSingleton.

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 74 matching lines @@
   UNSUPPORTED_OPTION   = 53,  // An unsupported legacy option was given.
   CPU_NOT_SUPPORTED    = 54,  // Current OS not supported
   REENABLE_UPDATES_SUCCEEDED = 55,  // Autoupdates are now enabled.
   REENABLE_UPDATES_FAILED = 56,  // Autoupdates could not be enabled.
   UNPACKING_FAILED     = 57,  // Unpacking the (possibly patched) uncompressed
                               // archive failed.
   IN_USE_DOWNGRADE     = 58,  // Successfully downgrade chrome but current
                               // version is still running.
   OLD_VERSION_DOWNGRADE = 59,  // Successfully downgrade chrome to an older
                                // version.
+  SETUP_SINGLETON_ACQUISITION_FAILED = 60,  // The setup process could not
+                                            // acquire the exclusive right to
+                                            // modify the Chrome installation.
 
-  MAX_INSTALL_STATUS   = 60,  // Bump this out to make space for new results.
+  MAX_INSTALL_STATUS   = 61,  // Bump this out to make space for new results.
 };
 
 // The type of an update archive.
 enum ArchiveType {
   UNKNOWN_ARCHIVE_TYPE,     // Unknown or uninitialized.
   FULL_ARCHIVE_TYPE,        // Full chrome.7z archive.
   INCREMENTAL_ARCHIVE_TYPE  // Incremental or differential archive.
 };
 
 // Stages of an installation from which a progress indication is derived.
@@ skipping 144 matching lines @@
 extern const char kCourgette[];
 extern const char kBsdiff[];
 
 // Name of the allocator (and associated file) for storing histograms to be
 // reported by Chrome during its next upload.
 extern const char kSetupHistogramAllocatorName[];
 
 }  // namespace installer
 
 #endif  // CHROME_INSTALLER_UTIL_UTIL_CONSTANTS_H_