Remove AstFactory from the front end.

pkg/front_end/lib/src/fasta/kernel/kernel_enum_builder.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.
 
 library fasta.kernel_enum_builder;
 
-import 'package:front_end/src/fasta/builder/ast_factory.dart' show AstFactory;
-
 import 'package:kernel/ast.dart'
     show
         Arguments,
         Class,
         Constructor,
         ConstructorInvocation,
         DirectPropertyGet,
         Expression,
         Field,
         FieldInitializer,
@@ skipping 62 matching lines @@
       this.intType,
       this.listType,
       this.objectType,
       this.stringType,
       LibraryBuilder parent,
       int charOffset)
       : super(metadata, 0, name, null, null, null, scope, constructors, parent,
             null, charOffset, cls);
 
   factory KernelEnumBuilder(
-      AstFactory astFactory,
       List<MetadataBuilder> metadata,
       String name,
       List<Object> constantNamesAndOffsets,
       KernelLibraryBuilder parent,
       int charOffset,
       int charEndOffset) {
     constantNamesAndOffsets ??= const <Object>[];
     // TODO(ahe): These types shouldn't be looked up in scope, they come
     // directly from dart:core.
     KernelTypeBuilder intType =
@@ skipping 167 matching lines @@
           new ConstructorInvocation(constructor, arguments, isConst: true);
     }
     return super.build(libraryBuilder, coreLibrary);
   }
 
   @override
   Builder findConstructorOrFactory(String name, int charOffset, Uri uri) {
     return null;
   }
 }