Unify the server and plugin versions of the generators

pkg/analysis_server/lib/src/plugin/result_converter.dart

 // Copyright (c) 2017, 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.
 
-import 'package:analysis_server/plugin/protocol/protocol.dart' as server;
+import 'package:analysis_server/protocol/protocol_generated.dart' as server;
 import 'package:analysis_server/src/protocol/protocol_internal.dart' as server;
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 
 /**
  * An object used to convert between similar objects defined by both the plugin
  * protocol and the server protocol.
  */
 class ResultConverter {
   /**
    * The decoder used to decode Json representations of server objects.
@@ skipping 67 matching lines @@
 
   server.RefactoringKind convertRefactoringKind(
       plugin.RefactoringKind feedback) {
     return new server.RefactoringKind.fromJson(decoder, '', feedback.toJson());
   }
 
   server.SourceChange convertSourceChange(plugin.SourceChange change) {
     return new server.SourceChange.fromJson(decoder, '', change.toJson());
   }
 }