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

sandbox/src/service_resolver_unittest.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.
 
 // This file contains unit tests for ServiceResolverThunk.
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/win/windows_version.h"
 #include "sandbox/src/resolver.h"
@@ skipping 102 matching lines @@
       ret = resolver->Setup(ntdll_base, NULL, function, NULL, function_entry,
                             thunk.get(), thunk_size, &used);
       CheckJump(service, thunk.get());
     }
   }
 
   return ret;
 }
 
 sandbox::ServiceResolverThunk* GetTestResolver(bool relaxed) {
-  if (base::win::GetWOW64Status() == base::win::WOW64_ENABLED)
+  if (base::win::OSInfo::GetInstance()->wow64_status() ==
+      base::win::OSInfo::WOW64_ENABLED)
     return new Wow64ResolverTest(relaxed);
   if (!sandbox::IsXPSP2OrLater())
     return new Win2kResolverTest(relaxed);
   return new WinXpResolverTest(relaxed);
 }
 
 NTSTATUS PatchNtdll(const char* function, bool relaxed) {
   sandbox::ServiceResolverThunk* resolver = GetTestResolver(relaxed);
 
   NTSTATUS ret = PatchNtdllWithResolver(function, relaxed, resolver);
@@ skipping 62 matching lines @@
     ::GetLastError();
 
   ret = PatchNtdllWithResolver("NtMapViewOfSection", true, resolver);
   EXPECT_EQ(STATUS_SUCCESS, ret) << "NtMapViewOfSection, last error: " <<
     ::GetLastError();
   delete resolver;
 #endif
 }
 
 }  // namespace