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

sandbox/src/sandbox_utils.cc

Index: sandbox/src/sandbox_utils.cc
===================================================================
--- sandbox/src/sandbox_utils.cc	(revision 80667)
+++ sandbox/src/sandbox_utils.cc	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -7,6 +7,7 @@
 #include <windows.h>
 
 #include "base/logging.h"
+#include "base/win/windows_version.h"
 #include "sandbox/src/internal_types.h"
 #include "sandbox/src/nt_internals.h"
 
@@ -56,33 +57,10 @@
 }
 
 bool IsXPSP2OrLater() {
-  OSVERSIONINFOEX version = {0};
-  version.dwOSVersionInfoSize = sizeof(version);
-  if (!::GetVersionEx(reinterpret_cast<OSVERSIONINFO*>(&version))) {
-    NOTREACHED();
-    return false;
-  }
-
-  // Vista or later
-  if (version.dwMajorVersion > 5)
-    return true;
-
-  // 2k, xp or 2003
-  if (version.dwMajorVersion == 5) {
-    // 2003
-    if (version.dwMinorVersion > 1)
-      return true;
-
-    // 2000
-    if (version.dwMinorVersion == 0)
-      return false;
-
-    // Windows Xp Sp2 or later
-    if (version.wServicePackMajor >= 2)
-      return true;
-  }
-
-  return false;
+  base::win::Version version = base::win::GetVersion();
+  return (version > base::win::VERSION_XP) ||
+      ((version == base::win::VERSION_XP) &&
+       (base::win::OSInfo::GetInstance()->service_pack().major >= 2));
 }
 
 void InitObjectAttribs(const std::wstring& name, ULONG attributes, HANDLE root,