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

chrome/browser/nacl_host/nacl_process_host.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 "build/build_config.h"
 
 #include "chrome/browser/nacl_host/nacl_process_host.h"
 
 #if defined(OS_POSIX)
 #include <fcntl.h>
@@ skipping 38 matching lines @@
   std::vector<nacl::Handle> sockets_for_sel_ldr;
 };
 
 NaClProcessHost::NaClProcessHost(const std::wstring& url)
     : BrowserChildProcessHost(NACL_LOADER_PROCESS, NULL),
       reply_msg_(NULL),
       internal_(new NaClInternal()),
       running_on_wow64_(false) {
   set_name(url);
 #if defined(OS_WIN)
-  running_on_wow64_ = (base::win::GetWOW64Status() == base::win::WOW64_ENABLED);
+  running_on_wow64_ = (base::win::OSInfo::GetInstance()->wow64_status() ==
+      base::win::OSInfo::WOW64_ENABLED);
 #endif
 }
 
 NaClProcessHost::~NaClProcessHost() {
   if (!reply_msg_)
     return;
 
   // nacl::Close() is not available at link time if DISABLE_NACL is
   // defined, but we still compile a bunch of other code from this
   // file anyway.  TODO(mseaborn): Make this less messy.
@@ skipping 222 matching lines @@
 }
 
 bool NaClProcessHost::OnMessageReceived(const IPC::Message& msg) {
   NOTREACHED() << "Invalid message with type = " << msg.type();
   return false;
 }
 
 bool NaClProcessHost::CanShutdown() {
   return true;
 }