Add serialization support to the JS DataSender and DataReceiver.

device/serial/data_stream_serialization.mojom

+// Copyright 2014 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.
+
+import "data_stream.mojom"
+
+module device.serial {
+
+// A serialized form of a DataSender.
+struct SerializedDataSender {
+  // The control channel to the DataSink to which this DataSender sends data.
+  DataSink sink;
+
+  // The data pipe this DataSender uses to send data to the DataSink.
+  handle<data_pipe_producer> data_pipe;
+
+  // The error to report for sends in progress when a fatal error occurs.
+  int32 fatal_error_value;
+};
+
+// A pending receive error.
+struct PendingReceiveError {
+  // The value of the error.
+  int32 error;
+
+  // The location of the error.
+  uint32 offset;
+};
+
+// A serialized form of a DataReceiver.
+struct SerializedDataReceiver {
+  // The control channel to the DataSource from which this DataReceiver receives
+  // data.
+  DataSource source;
+
+  // The data pipe this DataReceiver uses to receive data from the DataSource.
+  handle<data_pipe_consumer> data_pipe;
+
+  // The error to report for a receive in progress when a fatal error occurs.
+  int32 fatal_error_value;
+
+  // The number of bytes this DataReceiver has received from the DataSource.
+  uint32 bytes_received;
+
+  // Whether a Resume() message needs to be sent to the DataSource for it to
+  // resume sending data.
+  bool paused;
+
+  // The pending receive error if there is one.
+  PendingReceiveError? pending_error;
+};
+
+}