Add closure_test for kernel based members

pkg/compiler/lib/src/kernel/kernel_backend_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.kernel.backend_strategy;
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../backend_strategy.dart';
 import '../closure.dart';
@@ skipping 19 matching lines @@
 import '../ssa/types.dart';
 import '../types/types.dart';
 import '../universe/selector.dart';
 import '../universe/world_builder.dart';
 import '../universe/world_impact.dart';
 import '../world.dart';
 import 'closure.dart';
 import 'element_map_impl.dart';
 import 'kernel_strategy.dart';
 
+/// A backend strategy based on Kernel IR nodes.
+abstract class KernelBackendStrategy implements BackendStrategy {
+  KernelToElementMap get elementMap;
+  GlobalLocalsMap get globalLocalsMapForTesting;
+}
+
 /// Backend strategy that uses the kernel elements as the backend model.
 // TODO(johnniwinther): Replace this with a strategy based on the J-element
 // model.
-class KernelBackendStrategy implements BackendStrategy {
+class KernelBackendStrategyImpl implements KernelBackendStrategy {
   final Compiler _compiler;
   Sorter _sorter;
   ClosureConversionTask _closureDataLookup;
-  GlobalLocalsMap _globalLocalsMap = new GlobalLocalsMap();
+  final GlobalLocalsMap _globalLocalsMap = new GlobalLocalsMap();
 
-  KernelBackendStrategy(this._compiler);
+  KernelBackendStrategyImpl(this._compiler);
 
-  KernelToElementMap get _elementMap {
+  KernelToElementMap get elementMap {
     KernelFrontEndStrategy frontendStrategy = _compiler.frontendStrategy;
     return frontendStrategy.elementMap;
   }
 
+  GlobalLocalsMap get globalLocalsMapForTesting => _globalLocalsMap;
+
   @override
   ClosedWorldRefiner createClosedWorldRefiner(
       covariant KernelClosedWorld closedWorld) {
     return closedWorld;
   }
 
   @override
   Sorter get sorter {
     if (_sorter == null) {
-      KernelFrontEndStrategy frontendStrategy = _compiler.frontendStrategy;
-      _sorter = new KernelSorter(frontendStrategy.elementMap);
+      _sorter = new KernelSorter(elementMap);
     }
     return _sorter;
   }
 
   @override
   ClosureConversionTask get closureDataLookup =>
       _closureDataLookup ??= new KernelClosureConversionTask(
-          _compiler.measurer, _elementMap, _globalLocalsMap);
+          _compiler.measurer, 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);
   }
 
   @override
   SsaBuilder createSsaBuilder(CompilerTask task, JavaScriptBackend backend,
       SourceInformationStrategy sourceInformationStrategy) {
     return new KernelSsaBuilder(
-        task, backend.compiler, _elementMap, _globalLocalsMap);
+        task, backend.compiler, elementMap, _globalLocalsMap);
   }
 
   @override
   SourceInformationStrategy get sourceInformationStrategy =>
       const JavaScriptSourceInformationStrategy();
 }
 
 class KernelCodegenWorkItemBuilder implements WorkItemBuilder {
   final JavaScriptBackend _backend;
   final ClosedWorld _closedWorld;
@@ skipping 265 matching lines @@
   Iterable<ClassEntity> sortClasses(Iterable<ClassEntity> classes) {
     return classes.toList()
       ..sort((ClassEntity a, ClassEntity b) {
         int r = _compareLibraries(a.library, b.library);
         if (r != 0) return r;
         return _compareNodes(
             a, elementMap.getClassNode(a), b, elementMap.getClassNode(b));
       });
   }
 }