Remove peeking from parseTypedef and parseClassOrNamedMixinApplication.

pkg/front_end/lib/src/fasta/source/source_library_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.source_library_builder;
 
 import 'package:front_end/src/scanner/token.dart' show Token;
 
 import 'package:kernel/ast.dart' show ProcedureKind;
 
@@ skipping 501 matching lines @@
   final DeclarationBuilder<T> parent;
 
   final Map<String, Builder> members;
 
   final Map<String, Builder> constructors;
 
   final Map<String, Builder> setters;
 
   final List<T> types = <T>[];
 
-  final String name;
+  String name;
 
   final Map<ProcedureBuilder, DeclarationBuilder<T>> factoryDeclarations;
 
   DeclarationBuilder(this.members, this.setters, this.constructors,
       this.factoryDeclarations, this.name, this.parent);
 
   DeclarationBuilder.library()
       : this(<String, Builder>{}, <String, Builder>{}, null, null, null, null);
 
   DeclarationBuilder createNested(String name, bool hasMembers) {
@@ skipping 66 matching lines @@
   /// synthesize type variables on the factory matching the class'.
   void addFactoryDeclaration(
       ProcedureBuilder procedure, DeclarationBuilder<T> factoryDeclaration) {
     factoryDeclarations[procedure] = factoryDeclaration;
   }
 
   Scope toScope(Scope parent) {
     return new Scope(members, setters, parent, isModifiable: false);
   }
 }