Use entities in ClosedWorld interface

pkg/compiler/lib/src/enqueue.dart

 // Copyright (c) 2012, 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.enqueue;
 
 import 'dart:collection' show Queue;
 
 import 'cache_strategy.dart';
 import 'common/backend_api.dart' show Backend;
 import 'common/resolution.dart' show Resolution;
 import 'common/tasks.dart' show CompilerTask;
 import 'common/work.dart' show WorkItem;
 import 'common.dart';
 import 'compiler.dart' show Compiler, GlobalDependencyRegistry;
 import 'options.dart';
-import 'elements/resolution_types.dart' show DartType, InterfaceType;
 import 'elements/elements.dart'
     show
         AnalyzableElement,
         ClassElement,
         ConstructorElement,
         Element,
         Entity,
         MemberElement;
 import 'elements/entities.dart';
+import 'elements/resolution_types.dart' show DartType, InterfaceType;
 import 'native/native.dart' as native;
-import 'types/types.dart' show TypeMaskStrategy;
 import 'universe/world_builder.dart';
 import 'universe/use.dart'
     show DynamicUse, StaticUse, StaticUseKind, TypeUse, TypeUseKind;
 import 'universe/world_impact.dart'
     show ImpactStrategy, ImpactUseCase, WorldImpact, WorldImpactVisitor;
 import 'util/enumset.dart';
 import 'util/util.dart' show Setlet;
 import 'world.dart' show OpenWorld;
 
 class EnqueueTask extends CompilerTask {
@@ skipping 502 matching lines @@
   @override
   WorkItem createWorkItem(MemberElement element) {
     assert(invariant(element, element.isDeclaration));
     if (element.isMalformed) return null;
 
     assert(invariant(element, element is AnalyzableElement,
         message: 'Element $element is not analyzable.'));
     return _resolution.createWorkItem(element);
   }
 }