Move the wire protocol support into the public API

pkg/analysis_server/lib/src/channel/web_socket_channel.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 channel.web_socket;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/channel/channel.dart';
-import 'package:analysis_server/src/protocol.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
 
 /**
  * Instances of the class [WebSocketClientChannel] implement a
  * [ClientCommunicationChannel] that uses a [WebSocket] to communicate with
  * servers.
  */
 class WebSocketClientChannel implements ClientCommunicationChannel {
   /**
    * The socket being wrapped.
@@ skipping 107 matching lines @@
 
   @override
   void sendResponse(Response response) {
     ServerPerformanceStatistics.serverChannel.makeCurrentWhile(() {
       String jsonEncoding = JSON.encode(response.toJson());
       socket.add(jsonEncoding);
       instrumentationService.logResponse(jsonEncoding);
     });
   }
 }