Add a "native_support" service.

services/native_support/make_pty_pair.h

+// Copyright 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.
+
+#ifndef SERVICES_NATIVE_SUPPORT_MAKE_PTY_PAIR_H_
+#define SERVICES_NATIVE_SUPPORT_MAKE_PTY_PAIR_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/files/scoped_file.h"
+
+namespace native_support {
+
+// Makes a pseudoterminal master-slave pair of FDs. Returns true on success and
+// false on failure in which case it sets |*errno_value| appropriately (and
+// touches neither |master_fd| nor |slave_fd|).
+bool MakePtyPair(base::ScopedFD* master_fd,
+                 base::ScopedFD* slave_fd,
+                 int* errno_value);
+
+}  // namespace native_support
+
+#endif  // SERVICES_NATIVE_SUPPORT_MAKE_PTY_PAIR_H_