Handle static fields in js_model/model_test

pkg/compiler/lib/src/world.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.world;
 
 import 'closure.dart' show ClosureClassElement;
 import 'common.dart';
 import 'constants/constant_system.dart';
 import 'common_elements.dart' show CommonElements, ElementEnvironment;
@@ skipping 994 matching lines @@
   /// methods defined in [ClosedWorld].
   ClassSet getClassSet(ClassEntity cls) {
     assert(checkClass(cls));
     return _classSets[cls];
   }
 
   Iterable<TypedefElement> get allTypedefs => _allTypedefs;
 
   void _ensureFunctionSet() {
     if (_allFunctions == null) {
+      // [FunctionSet] is created lazily because it is not used when we switch
+      // from a frontend to a backend model before inference.
       _allFunctions = new FunctionSet(liveInstanceMembers);
     }
   }
 
   TypeMask computeReceiverType(Selector selector, TypeMask mask) {
     _ensureFunctionSet();
     return _allFunctions.receiverType(selector, mask, this);
   }
 
   Iterable<MemberEntity> locateMembers(Selector selector, TypeMask mask) {
@@ skipping 287 matching lines @@
     // does not see generative constructor bodies because they are
     // created by the backend. Also, it does not make any distinction
     // between a constructor and its body for side effects. This
     // implies that currently, the side effects of a constructor body
     // contain the side effects of the initializers.
     assert(!element.isGenerativeConstructorBody);
     assert(!element.isField);
     return super.getSideEffectsOfElement(element);
   }
 }