Parse factory constructors with Fasta.

pkg/analyzer/lib/src/summary/fasta/summary_builder.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.
 
 /// Logic to build unlinked summaries.
 library summary.src.summary_builder;
 
 import 'package:front_end/src/fasta/parser/class_member_parser.dart';
 import 'package:front_end/src/fasta/parser/identifier_context.dart';
 import 'package:front_end/src/fasta/parser/parser.dart';
@@ skipping 966 matching lines @@
     String uri = pop();
     // ignore: strong_mode_down_cast_composite
     List<UnlinkedExpr> metadata = pop();
     topScope.unit.exports
         .add(new UnlinkedExportNonPublicBuilder(annotations: metadata));
     topScope.publicNamespace.exports.add(new UnlinkedExportPublicBuilder(
         uri: uri, combinators: combinators, configurations: conditionalUris));
     checkEmpty();
   }
 
-  void endFactoryMethod(Token beginToken, Token endToken) {
+  void endFactoryMethod(
+      Token beginToken, Token factoryKeyword, Token endToken) {
     debugEvent("FactoryMethod");
     throw new UnimplementedError(); // TODO(paulberry)
     // pop(); // async-modifiers
     // /* List<FormalParameterBuilder> formals = */ pop();
     // var name = pop();
     // /* List<MetadataBuilder> metadata = */ pop();
   }
 
   void endFieldInitializer(Token assignmentOperator) {
     debugEvent("FieldInitializer $typeSeen $assignmentOperator");
@@ skipping 591 matching lines @@
 }
 
 /// Internal representation of an initialized name.
 class _InitializedName {
   final String name;
   final UnlinkedExecutableBuilder initializer;
   _InitializedName(this.name, this.initializer);
 
   toString() => "II:" + (initializer != null ? "$name = $initializer" : name);
 }