Restructure sandbox code to reduce dependencies pulled in by intercept code.

sandbox/win/src/sandbox_globals.cc

+// Copyright 2013 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 <windows.h>
+
+#include "sandbox/win/src/sandbox_nt_types.h"
+#include "sandbox/win/src/sandbox_types.h"
+
+namespace sandbox {
+
+// The section for IPC and policy.
+SANDBOX_INTERCEPT HANDLE g_shared_section = NULL;
+
+// This is the list of all imported symbols from ntdll.dll.
+SANDBOX_INTERCEPT NtExports g_nt = {};
+
+}  // namespace sandbox