Move some basic early process init into Service Manager

services/service_manager/embedder/switches.cc

+// Copyright 2017 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 "services/service_manager/embedder/switches.h"
+
+namespace switches {
+
+// Describes the file descriptors passed to a child process in the following
+// list format:
+//
+//     <file_id>:<descriptor_id>,<file_id>:<descriptor_id>,...
+//
+// where <file_id> is an ID string from the manifest of the service being
+// launched and <descriptor_id> is the numeric identifier of the descriptor for
+// the child process can use to retrieve the file descriptor from the
+// global descriptor table.
+const char kSharedFiles[] = "shared-files";
+
+}  // namespace switches