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

base/file_version_info_win.cc

Index: base/file_version_info_win.cc
===================================================================
--- base/file_version_info_win.cc	(revision 80667)
+++ base/file_version_info_win.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.
 
@@ -12,9 +12,6 @@
 #include "base/path_service.h"
 #include "base/threading/thread_restrictions.h"
 
-// This has to be last.
-#include <strsafe.h>
-
 FileVersionInfoWin::FileVersionInfoWin(void* data, int language, int code_page)
     : language_(language), code_page_(code_page) {
   base::ThreadRestrictions::AssertIOAllowed();