Add the child_port Mach subsystem

util/mach/child_port_types.h

Index: util/mach/child_port_types.h
diff --git a/util/mach/child_port_types.h b/util/mach/child_port_types.h
new file mode 100644
index 0000000000000000000000000000000000000000..d0760a73f4b6e9e2289cdcebae4822813bad414c
--- /dev/null
+++ b/util/mach/child_port_types.h
@@ -0,0 +1,26 @@
+// Copyright 2014 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CRASHPAD_UTIL_MACH_CHILD_PORT_TYPES_H_
+#define CRASHPAD_UTIL_MACH_CHILD_PORT_TYPES_H_
+
+#include <mach/mach.h>
+#include <stdint.h>
+
+// This file is #included by C (non-C++) files, and must remain strictly C.
+
+typedef mach_port_t child_port_server_t;
+typedef uint64_t child_port_token_t;
+
+#endif  // CRASHPAD_UTIL_MACH_CHILD_PORT_TYPES_H_