Add an AST factory method for fieldDeclaration with all optional named parameters.

pkg/analyzer/lib/src/dart/ast/ast_factory.dart

 // Copyright (c) 2016, 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:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/ast_factory.dart';
 import 'package:analyzer/src/dart/ast/ast.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 import 'package:front_end/src/scanner/token.dart';
 import 'package:meta/meta.dart';
@@ skipping 343 matching lines @@
       new ExtendsClauseImpl(extendsKeyword, superclass);
 
   @override
   FieldDeclaration fieldDeclaration(
           Comment comment,
           List<Annotation> metadata,
           Token staticKeyword,
           VariableDeclarationList fieldList,
           Token semicolon) =>
       new FieldDeclarationImpl(
-          comment, metadata, staticKeyword, fieldList, semicolon);
+          comment, metadata, null, staticKeyword, fieldList, semicolon);
+
+  @override
+  FieldDeclaration fieldDeclaration2(
+          {Comment comment,
+          List<Annotation> metadata,
+          Token covariantKeyword,
+          Token staticKeyword,
+          @required VariableDeclarationList fieldList,
+          @required Token semicolon}) =>
+      new FieldDeclarationImpl(comment, metadata, covariantKeyword,
+          staticKeyword, fieldList, semicolon);
 
   @override
   FieldFormalParameter fieldFormalParameter(
           Comment comment,
           List<Annotation> metadata,
           Token keyword,
           TypeAnnotation type,
           Token thisKeyword,
           Token period,
           SimpleIdentifier identifier,
@@ skipping 575 matching lines @@
 
   @override
   WithClause withClause(Token withKeyword, List<TypeName> mixinTypes) =>
       new WithClauseImpl(withKeyword, mixinTypes);
 
   @override
   YieldStatement yieldStatement(Token yieldKeyword, Token star,
           Expression expression, Token semicolon) =>
       new YieldStatementImpl(yieldKeyword, star, expression, semicolon);
 }