Make the windows_version.h functions threadsafe by using a singleton.

chrome/browser/ui/views/about_chrome_view.cc

 // Copyright (c) 2011 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/browser/ui/views/about_chrome_view.h"
 
 #if defined(OS_WIN)
 #include <commdlg.h>
 #endif  // defined(OS_WIN)
 
@@ skipping 514 matching lines @@
       update_available_indicator_.SetVisible(false);
       parent->AddChildView(&timeout_indicator_);
       timeout_indicator_.SetVisible(false);
 
 #if defined(OS_WIN)
       // On-demand updates for Chrome don't work in Vista RTM when UAC is turned
       // off. So, in this case we just want the About box to not mention
       // on-demand updates. Silent updates (in the background) should still
       // work as before - enabling UAC or installing the latest service pack
       // for Vista is another option.
-      int service_pack_major = 0, service_pack_minor = 0;
-      base::win::GetServicePackLevel(&service_pack_major, &service_pack_minor);
       if (!(base::win::GetVersion() == base::win::VERSION_VISTA &&
-            (service_pack_major == 0) &&
+            (base::win::OSInfo::GetInstance()->service_pack().major == 0) &&
             !base::win::UserAccountControlIsEnabled())) {
         UpdateStatus(UPGRADE_CHECK_STARTED, GOOGLE_UPDATE_NO_ERROR);
         // CheckForUpdate(false, ...) means don't upgrade yet.
         google_updater_->CheckForUpdate(false, window());
       }
 #elif defined(OS_CHROMEOS)
       UpdateStatus(UPGRADE_CHECK_STARTED, GOOGLE_UPDATE_NO_ERROR);
       // CheckForUpdate(false, ...) means don't upgrade yet.
       google_updater_->CheckForUpdate(false, window());
 #endif
@@ skipping 282 matching lines @@
   // We have updated controls on the parent, so we need to update its layout.
   parent()->Layout();
 
   // Check button may have appeared/disappeared. We cannot call this during
   // ViewHierarchyChanged because the |window()| pointer hasn't been set yet.
   if (window())
     GetDialogClientView()->UpdateDialogButtons();
 }
 
 #endif