Support Serializing and Deserializing RepeatedField / RepeatedPtrField in IPC::Message

ipc/test_proto.proto

+// 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.
+
+syntax = "proto2";
+option optimize_for = LITE_RUNTIME;
+package ipc_message_utils_test;
+
+// This is a simple dummy protocol buffer that is used for testing handling of
+// protocol buffers in ipc_message_utils.
+
+message TestMessage1 {
+    optional int32 number = 1;
+}
+
+message TestMessage2 {
+    repeated int32 numbers = 1;
+    repeated string strings = 2;
+    repeated TestMessage1 messages = 3;
+}