Make server use the common protocol classes

pkg/analysis_server/lib/src/services/completion/dart/utilities.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.
 
 /**
  * A collection of utility methods used by completion contributors.
  */
-import 'package:analysis_server/protocol/protocol_generated.dart' as protocol
-    show Element, ElementKind;
 import 'package:analysis_server/src/ide_options.dart';
 import 'package:analysis_server/src/protocol_server.dart'
     show CompletionSuggestion, CompletionSuggestionKind, Location;
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/correction/flutter_util.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_ast_factory.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer_plugin/protocol/protocol_common.dart' as protocol
+    show Element, ElementKind;
 
 /**
  * The name of the type `dynamic`;
  */
 const DYNAMIC = 'dynamic';
 
 /**
  * A marker used in place of `null` when a function has no return type.
  */
 final TypeName NO_RETURN_TYPE = astFactory.typeName(
@@ skipping 218 matching lines @@
     }
     return name;
   } else if (type is GenericFunctionType) {
     // TODO(brianwilkerson) Implement this.
   }
   return DYNAMIC;
 }
 
 //TODO(pq): fix to use getDefaultStringParameterValue()
 String _getDefaultValue(ParameterElement param) => 'null';