Move the wire protocol support into the public API

pkg/analysis_server/test/channel/byte_stream_channel_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library test.channel.byte_stream;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/channel/byte_stream_channel.dart';
-import 'package:analysis_server/src/protocol.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:unittest/unittest.dart';
 
 import '../mocks.dart';
 import '../utils.dart';
 
 main() {
   initializeTestEnvironment();
   group('ByteStreamClientChannel', () {
     setUp(ByteStreamClientChannelTest.setUp);
@@ skipping 236 matching lines @@
     doneFuture = doneCompleter.future;
     channel.listen((Request request) {
       requestStreamController.add(request);
     }, onError: (error) {
       errorStreamController.add(error);
     }, onDone: () {
       doneCompleter.complete();
     });
   }
 }