Add closure_test for kernel based members

pkg/compiler/lib/src/js_model/js_strategy.dart

 // Copyright (c) 2017, 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.js_model.strategy;
 
-import '../backend_strategy.dart';
 import '../closure.dart' show ClosureConversionTask;
 import '../common/tasks.dart';
 import '../common_elements.dart';
 import '../compiler.dart';
 import '../elements/elements.dart' show TypedefElement;
 import '../elements/entities.dart';
 import '../enqueue.dart';
 import '../io/source_information.dart';
 import '../js_emitter/sorter.dart';
 import '../js/js_source_mapping.dart';
 import '../js_backend/backend.dart';
 import '../js_backend/backend_usage.dart';
 import '../js_backend/constant_system_javascript.dart';
 import '../js_backend/interceptor_data.dart';
 import '../js_backend/native_data.dart';
 import '../kernel/closure.dart';
 import '../kernel/element_map.dart';
 import '../kernel/element_map_impl.dart';
 import '../kernel/kernel_backend_strategy.dart';
 import '../kernel/kernel_strategy.dart';
 import '../ssa/ssa.dart';
 import '../universe/class_set.dart';
 import '../universe/world_builder.dart';
 import '../util/emptyset.dart';
 import '../world.dart';
 import 'elements.dart';
 
-class JsBackendStrategy implements BackendStrategy {
+class JsBackendStrategy implements KernelBackendStrategy {
   final Compiler _compiler;
   final JsToFrontendMap _map = new JsToFrontendMapImpl();
   ElementEnvironment _elementEnvironment;
   CommonElements _commonElements;
-  KernelToElementMap __elementMap;
+  KernelToElementMap _elementMap;
   ClosureConversionTask _closureDataLookup;
-  GlobalLocalsMap _globalLocalsMap = new GlobalLocalsMap();
+  final GlobalLocalsMap _globalLocalsMap = new GlobalLocalsMap();
 
   JsBackendStrategy(this._compiler);
 
-  KernelToElementMap get _elementMap {
-    if (__elementMap == null) {
+  KernelToElementMap get elementMap {
+    if (_elementMap == null) {
       KernelFrontEndStrategy strategy = _compiler.frontendStrategy;
       KernelToElementMap elementMap = strategy.elementMap;
-      __elementMap = new JsKernelToElementMap(
+      _elementMap = new JsKernelToElementMap(
           _map, _elementEnvironment, _commonElements, elementMap);
     }
-    return __elementMap;
+    return _elementMap;
   }
 
+  GlobalLocalsMap get globalLocalsMapForTesting => _globalLocalsMap;
+
   @override
   ClosedWorldRefiner createClosedWorldRefiner(ClosedWorld closedWorld) {
     _elementEnvironment =
         new JsElementEnvironment(_map, closedWorld.elementEnvironment);
     _commonElements = new JsCommonElements(_map, closedWorld.commonElements);
     BackendUsage backendUsage =
         new JsBackendUsage(_map, closedWorld.backendUsage);
     NativeData nativeData = new JsNativeData(_map, closedWorld.nativeData);
     InterceptorData interceptorData = new InterceptorDataImpl(
         nativeData,
@@ skipping 59 matching lines @@
   }
 
   @override
   Sorter get sorter {
     throw new UnimplementedError('JsBackendStrategy.sorter');
   }
 
   @override
   ClosureConversionTask get closureDataLookup =>
       _closureDataLookup ??= new KernelClosureConversionTask(
-          _compiler.measurer, _elementMap, _globalLocalsMap);
+          _compiler.measurer, elementMap, _globalLocalsMap);
 
   @override
   SourceInformationStrategy get sourceInformationStrategy =>
       const JavaScriptSourceInformationStrategy();
 
   @override
   SsaBuilder createSsaBuilder(CompilerTask task, JavaScriptBackend backend,
       SourceInformationStrategy sourceInformationStrategy) {
     return new KernelSsaBuilder(
-        task, backend.compiler, _elementMap, _globalLocalsMap);
+        task, backend.compiler, elementMap, _globalLocalsMap);
   }
 
   @override
   WorkItemBuilder createCodegenWorkItemBuilder(ClosedWorld closedWorld) {
     return new KernelCodegenWorkItemBuilder(_compiler.backend, closedWorld);
   }
 
   @override
   CodegenWorldBuilder createCodegenWorldBuilder(
       NativeBasicData nativeBasicData,
       ClosedWorld closedWorld,
       SelectorConstraintsStrategy selectorConstraintsStrategy) {
     return new KernelCodegenWorldBuilder(
-        _elementMap,
+        elementMap,
         closedWorld.elementEnvironment,
         nativeBasicData,
         closedWorld,
         selectorConstraintsStrategy);
   }
 }