Implement subtype relation for kernel based elements.

tests/compiler/dart2js/serialization/model_test_helper.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.serialization_model_test;
 
 import 'dart:async';
 import 'dart:io';
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'package:compiler/src/closure.dart';
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/common.dart';
 import 'package:compiler/src/constants/values.dart';
 import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/elements/resolution_types.dart';
+import 'package:compiler/src/elements/types.dart';
 import 'package:compiler/src/deferred_load.dart';
 import 'package:compiler/src/elements/elements.dart';
 import 'package:compiler/src/elements/entities.dart';
 import 'package:compiler/src/enqueue.dart';
 import 'package:compiler/src/filenames.dart';
 import 'package:compiler/src/js_backend/js_backend.dart';
 import 'package:compiler/src/js_backend/backend_usage.dart';
 import 'package:compiler/src/serialization/equivalence.dart';
 import 'package:compiler/src/tree/nodes.dart';
 import 'package:compiler/src/universe/class_set.dart';
@@ skipping 82 matching lines @@
         verbose: verbose);
     checkBackendInfo(compilerNormal, compilerDeserialized, verbose: verbose);
   });
 }
 
 void checkResolutionEnqueuers(
     BackendUsage backendUsage1,
     BackendUsage backendUsage2,
     ResolutionEnqueuer enqueuer1,
     ResolutionEnqueuer enqueuer2,
-    {bool typeEquivalence(ResolutionDartType a, ResolutionDartType b):
-        areTypesEquivalent,
+    {bool elementEquivalence(Entity a, Entity b): areElementsEquivalent,
+    bool typeEquivalence(DartType a, DartType b): areTypesEquivalent,
     bool elementFilter(Element element),
     bool verbose: false}) {
   checkSets(enqueuer1.processedEntities, enqueuer2.processedEntities,
-      "Processed element mismatch", areElementsEquivalent, elementFilter: (e) {
+      "Processed element mismatch", elementEquivalence, elementFilter: (e) {
     return elementFilter != null ? elementFilter(e) : true;
   }, verbose: verbose);
 
-  ElementResolutionWorldBuilder worldBuilder1 = enqueuer1.worldBuilder;
-  ElementResolutionWorldBuilder worldBuilder2 = enqueuer2.worldBuilder;
+  ResolutionWorldBuilderBase worldBuilder1 = enqueuer1.worldBuilder;
+  ResolutionWorldBuilderBase worldBuilder2 = enqueuer2.worldBuilder;
 
   checkMaps(
       worldBuilder1.getInstantiationMap(),
       worldBuilder2.getInstantiationMap(),
       "Instantiated classes mismatch",
-      areElementsEquivalent,
+      elementEquivalence,
       (a, b) => areInstantiationInfosEquivalent(a, b, typeEquivalence),
       verbose: verbose);
 
   checkSets(
       enqueuer1.worldBuilder.directlyInstantiatedClasses,
       enqueuer2.worldBuilder.directlyInstantiatedClasses,
       "Directly instantiated classes mismatch",
-      areElementsEquivalent,
+      elementEquivalence,
       verbose: verbose);
 
   checkSets(
       enqueuer1.worldBuilder.instantiatedTypes,
       enqueuer2.worldBuilder.instantiatedTypes,
       "Instantiated types mismatch",
       typeEquivalence,
       verbose: verbose);
 
   checkSets(enqueuer1.worldBuilder.isChecks, enqueuer2.worldBuilder.isChecks,
@@ skipping 301 matching lines @@
 }
 
 bool areInstancesEquivalent(Instance instance1, Instance instance2,
     bool typeEquivalence(ResolutionDartType a, ResolutionDartType b)) {
   ResolutionInterfaceType type1 = instance1.type;
   ResolutionInterfaceType type2 = instance2.type;
   return typeEquivalence(type1, type2) &&
       instance1.kind == instance2.kind &&
       instance1.isRedirection == instance2.isRedirection;
 }