Unify the server and plugin versions of the generators

pkg/analysis_server/lib/src/plugin/request_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 RequestConverter {
   plugin.AnalysisReanalyzeParams convertAnalysisReanalyzeParams(
       server.AnalysisReanalyzeParams params) {
@@ skipping 47 matching lines @@
     } else if (overlay is server.RemoveContentOverlay) {
       return new plugin.RemoveContentOverlay();
     }
     return null;
   }
 
   plugin.SourceEdit convertSourceEdit(server.SourceEdit edit) {
     return new plugin.SourceEdit(edit.offset, edit.length, edit.replacement);
   }
 }