Split World usage into open, inference, and closed world.

tests/compiler/dart2js/map_tracer_test.dart

 // Copyright (c) 2014, 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.
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 import 'package:compiler/src/types/types.dart'
     show MapTypeMask, TypeMask;
 
 import 'compiler_helper.dart';
@@ skipping 196 matching lines @@
   doTest('{presetKey : anInt}', "presetKey", "anInt");
   // Test preset map of <Double,uint32>
   doTest('{aDouble : anInt}', "aDouble", "anInt");
 }
 
 void doTest(String allocation, [String keyElement,
             String valueElement]) {
   Uri uri = new Uri(scheme: 'source');
   var compiler = compilerFor(generateTest(allocation), uri,
       expectedErrors: 0, expectedWarnings: 1);
-  var classWorld = compiler.world;
+  var classWorld = compiler.closedWorld;
   asyncTest(() => compiler.run(uri).then((_) {
     var keyType, valueType;
     var commonMasks = compiler.commonMasks;
     var typesInferrer = compiler.globalInference.typesInferrer;
     var emptyType = new TypeMask.nonNullEmpty();
     var aKeyType =
         typesInferrer.getTypeOfElement(findElement(compiler, 'aKey'));
     if (keyElement != null) {
       keyType =
           typesInferrer.getTypeOfElement(findElement(compiler, keyElement));
@@ skipping 48 matching lines @@
     checkType('mapStoredInListButEscapes', K(commonMasks.dynamicType),
                                            V(commonMasks.dynamicType));
     checkType('mapStoredInMap', K(aKeyType), V(commonMasks.uint31Type));
     checkType('mapStoredInMapButEscapes', K(commonMasks.dynamicType),
                                           V(commonMasks.dynamicType));
 
     checkType('mapUnset', K(emptyType), V(emptyType));
     checkType('mapOnlySetWithConstraint', K(aKeyType), V(emptyType));
   }));
 }