Remove sandbox on Windows.

sandbox/win/src/sandbox_rand.cc

-// Copyright (c) 2015 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 "sandbox/win/src/sandbox_rand.h"
-
-#include <windows.h>
-
-// #define needed to link in RtlGenRandom(), a.k.a. SystemFunction036.  See the
-// "Community Additions" comment on MSDN here:
-// http://msdn.microsoft.com/en-us/library/windows/desktop/aa387694.aspx
-#define SystemFunction036 NTAPI SystemFunction036
-#include <NTSecAPI.h>
-#undef SystemFunction036
-
-namespace sandbox {
-
-bool GetRandom(unsigned int* random_value) {
-  return RtlGenRandom(random_value, sizeof(unsigned int)) != FALSE;
-}
-
-}  // namespace sandbox