dart2js: use WorldImpact for dump_info

pkg/compiler/lib/src/universe/world_impact.dart

 // Copyright (c) 2015, 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 dart2js.universe.world_impact;
 
 import '../dart_types.dart' show
     DartType,
     InterfaceType;
 import '../elements/elements.dart' show
@@ skipping 44 matching lines @@
     add('type uses', worldImpact.typeUses);
   }
 }
 
 class WorldImpactBuilder {
   // TODO(johnniwinther): Do we benefit from lazy initialization of the
   // [Setlet]s?
   Setlet<DynamicUse> _dynamicUses;
   Setlet<StaticUse> _staticUses;
   Setlet<TypeUse> _typeUses;
-  Setlet<LocalFunctionElement> _closures;
 
   void registerDynamicUse(DynamicUse dynamicUse) {
     assert(dynamicUse != null);
     if (_dynamicUses == null) {
       _dynamicUses = new Setlet<DynamicUse>();
     }
     _dynamicUses.add(dynamicUse);
   }
 
   Iterable<DynamicUse> get dynamicUses {
@@ skipping 79 matching lines @@
     return _staticUses != null ? _staticUses : worldImpact.staticUses;
   }
 
   String toString() {
     StringBuffer sb = new StringBuffer();
     sb.write('TransformedWorldImpact($worldImpact)');
     WorldImpact.printOn(sb, this);
     return sb.toString();
   }
 }