Move the wire protocol support into the public API

pkg/analysis_server/lib/src/socket_server.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 socket.server;
 
 import 'package:analysis_server/plugin/analysis/resolver_provider.dart';
+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/plugin/server_plugin.dart';
-import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/index/local_file_index.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:analyzer/source/pub_package_map_provider.dart';
 import 'package:analyzer/src/generated/sdk_io.dart';
 import 'package:plugin/plugin.dart';
 
 /**
  * Instances of the class [SocketServer] implement the common parts of
@@ skipping 66 matching lines @@
         index,
         serverPlugin,
         analysisServerOptions,
         defaultSdk,
         instrumentationService,
         packageResolverProvider: packageResolverProvider,
         rethrowExceptions: false);
     analysisServer.userDefinedPlugins = userDefinedPlugins;
   }
 }