Exit the installer gracefully if the processor doesn't support SSE2.

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 71 matching lines @@
   WAIT_FOR_EXISTING_FAILED,    // 48. OS error waiting for existing setup.exe.
   PATCH_INVALID_ARGUMENTS,     // 49. The arguments of --patch were missing or
                                // they were invalid for any reason.
   DIFF_PATCH_SOURCE_MISSING,   // 50. No previous version archive found for
                                // differential update.
   UNUSED_BINARIES,             // 51. No multi-install products to update. The
                                // binaries will be uninstalled if they are not
                                // in use.
   UNUSED_BINARIES_UNINSTALLED,  // 52. The binaries were uninstalled.
   UNSUPPORTED_OPTION,          // 53. An unsupported legacy option was given.
+  CPU_NOT_SUPPORTED,           // 54. Current OS not supported
   // Friendly reminder: note the COMPILE_ASSERT below.
 };
 
 
 // Existing InstallStatus values must not change.  Always add to the end.
-COMPILE_ASSERT(installer::UNSUPPORTED_OPTION == 53,
+COMPILE_ASSERT(installer::CPU_NOT_SUPPORTED == 54,
                dont_change_enum);
 
 // 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 reported through Google Update on failure.
@@ skipping 150 matching lines @@
 const int kCourgetteErrorOffset = 300;
 const int kBsdiffErrorOffset = 600;
 
 // Arguments to --patch switch
 extern const char kCourgette[];
 extern const char kBsdiff[];
 
 }  // namespace installer
 
 #endif  // CHROME_INSTALLER_UTIL_UTIL_CONSTANTS_H_