Change signature of resolveConstructors.

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:kernel/ast.dart' show AsyncMarker, ProcedureKind;
 
 import '../combinator.dart' show Combinator;
 
@@ skipping 437 matching lines @@
     int typeCount = types.length;
     for (T t in types) {
       t.resolveIn(scope);
     }
     forEach((String name, Builder member) {
       typeCount += member.resolveTypes(this);
     });
     return typeCount;
   }
 
+  @override
   int resolveConstructors(_) {
     int count = 0;
     forEach((String name, Builder member) {
       count += member.resolveConstructors(this);
     });
     return count;
   }
 
   List<TypeVariableBuilder> copyTypeVariables(
       List<TypeVariableBuilder> original);
@@ skipping 78 matching lines @@
   }
 
   /// Called to register [procedure] as a factory whose types are collected in
   /// [factoryDeclaration]. Later, once the class has been built, we can
   /// synthesize type variables on the factory matching the class'.
   void addFactoryDeclaration(
       ProcedureBuilder procedure, DeclarationBuilder<T> factoryDeclaration) {
     factoryDeclarations[procedure] = factoryDeclaration;
   }
 }