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

chrome/installer/setup/setup_main.cc

 // 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.
 
 #include "chrome/installer/setup/setup_main.h"
 
 #include <windows.h>
 #include <msi.h>
 #include <shellapi.h>
 #include <shlobj.h>
@@ skipping 1655 matching lines @@
   // deletion at reboot when this scope closes.
   VLOG(1) << "Deleting temporary directory " << temp_path.path().value();
 
   return install_status;
 }
 
 }  // namespace installer
 
 int WINAPI wWinMain(HINSTANCE instance, HINSTANCE prev_instance,
                     wchar_t* command_line, int show_command) {
+  // Check to see if the CPU is supported before doing anything else. There's
+  // very little than can safely be accomplished if the CPU isn't supported
+  // since dependent libraries (e.g., base) may use invalid instructions.
+  if (!installer::IsProcessorSupported())
+    return installer::CPU_NOT_SUPPORTED;
+
   // The exit manager is in charge of calling the dtors of singletons.
   base::AtExitManager exit_manager;
   CommandLine::Init(0, NULL);
 
   const MasterPreferences& prefs = MasterPreferences::ForCurrentProcess();
   installer::InitInstallerLogging(prefs);
 
   const CommandLine& cmd_line = *CommandLine::ForCurrentProcess();
   VLOG(1) << "Command Line: " << cmd_line.GetCommandLineString();
 
@@ skipping 125 matching lines @@
     // Note that we allow the status installer::UNINSTALL_REQUIRES_REBOOT
     // to pass through, since this is only returned on uninstall which is
     // never invoked directly by Google Update.
     return_code = InstallUtil::GetInstallReturnCode(install_status);
   }
 
   VLOG(1) << "Installation complete, returning: " << return_code;
 
   return return_code;
 }