Merge CommonElements and BackendHelpers!

tests/compiler/dart2js/kernel/closed_world_test.dart

 // Copyright (c) 2016, 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.
 
 // Tests that the closed world computed from [WorldImpact]s derived from kernel
 // is equivalent to the original computed from resolution.
 library dart2js.kernel.closed_world_test;
 
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/commandline_options.dart';
 import 'package:compiler/src/common.dart';
 import 'package:compiler/src/common_elements.dart';
 import 'package:compiler/src/common/backend_api.dart';
 import 'package:compiler/src/common/resolution.dart';
 import 'package:compiler/src/compiler.dart';
 import 'package:compiler/src/deferred_load.dart';
 import 'package:compiler/src/elements/resolution_types.dart';
 import 'package:compiler/src/elements/elements.dart';
 import 'package:compiler/src/enqueue.dart';
 import 'package:compiler/src/js_backend/backend.dart';
-import 'package:compiler/src/js_backend/backend_helpers.dart';
 import 'package:compiler/src/js_backend/backend_impact.dart';
 import 'package:compiler/src/js_backend/backend_usage.dart';
 import 'package:compiler/src/js_backend/custom_elements_analysis.dart';
 import 'package:compiler/src/js_backend/native_data.dart';
 import 'package:compiler/src/js_backend/interceptor_data.dart';
 import 'package:compiler/src/js_backend/lookup_map_analysis.dart';
 import 'package:compiler/src/js_backend/mirrors_analysis.dart';
 import 'package:compiler/src/js_backend/mirrors_data.dart';
 import 'package:compiler/src/js_backend/no_such_method_registry.dart';
 import 'package:compiler/src/js_backend/resolution_listener.dart';
@@ skipping 105 matching lines @@
         verbose: arguments.verbose);
   });
 }
 
 EnqueuerListener createResolutionEnqueuerListener(Compiler compiler) {
   JavaScriptBackend backend = compiler.backend;
   return new ResolutionEnqueuerListener(
       compiler.options,
       compiler.elementEnvironment,
       compiler.commonElements,
-      backend.helpers,
       backend.impacts,
       backend.backendClasses,
       backend.nativeBasicData,
       backend.interceptorDataBuilder,
       backend.backendUsageBuilder,
       backend.rtiNeedBuilder,
       backend.mirrorsDataBuilder,
       backend.noSuchMethodRegistry,
       backend.customElementsResolutionAnalysis,
       backend.lookupMapResolutionAnalysis,
       backend.mirrorsResolutionAnalysis,
       new TypeVariableResolutionAnalysis(compiler.elementEnvironment,
           backend.impacts, backend.backendUsageBuilder),
       backend.nativeResolutionEnqueuer,
       compiler.deferredLoadTask,
       backend.kernelTask);
 }
 
 EnqueuerListener createKernelResolutionEnqueuerListener(CompilerOptions options,
     DeferredLoadTask deferredLoadTask, KernelWorldBuilder worldBuilder) {
   ElementEnvironment elementEnvironment = worldBuilder.elementEnvironment;
   CommonElements commonElements = worldBuilder.commonElements;
-  BackendHelpers helpers =
-      new BackendHelpers(elementEnvironment, commonElements);
-  BackendImpacts impacts = new BackendImpacts(options, commonElements, helpers);
+  BackendImpacts impacts = new BackendImpacts(options, commonElements);
 
   // TODO(johnniwinther): Create Kernel based implementations for these:
   NativeBasicData nativeBasicData;
   RuntimeTypesNeedBuilder rtiNeedBuilder;
   MirrorsDataBuilder mirrorsDataBuilder;
   CustomElementsResolutionAnalysis customElementsResolutionAnalysis;
   LookupMapResolutionAnalysis lookupMapResolutionAnalysis;
   MirrorsResolutionAnalysis mirrorsResolutionAnalysis;
 
   BackendClasses backendClasses = new JavaScriptBackendClasses(
-      elementEnvironment, helpers, nativeBasicData);
+      elementEnvironment, commonElements, nativeBasicData);
   InterceptorDataBuilder interceptorDataBuilder =
       new InterceptorDataBuilderImpl(
-          nativeBasicData, helpers, elementEnvironment, commonElements);
+          nativeBasicData, elementEnvironment, commonElements);
   BackendUsageBuilder backendUsageBuilder =
-      new BackendUsageBuilderImpl(commonElements, helpers);
+      new BackendUsageBuilderImpl(commonElements);
   NoSuchMethodRegistry noSuchMethodRegistry = new NoSuchMethodRegistry(
-      helpers, new KernelNoSuchMethodResolver(worldBuilder));
+      commonElements, new KernelNoSuchMethodResolver(worldBuilder));
   NativeResolutionEnqueuer nativeResolutionEnqueuer =
       new NativeResolutionEnqueuer(
           options,
           elementEnvironment,
           commonElements,
-          helpers,
           backendClasses,
           backendUsageBuilder,
           new KernelNativeClassResolver(worldBuilder));
 
   return new ResolutionEnqueuerListener(
       options,
       elementEnvironment,
       commonElements,
-      helpers,
       impacts,
       backendClasses,
       nativeBasicData,
       interceptorDataBuilder,
       backendUsageBuilder,
       rtiNeedBuilder,
       mirrorsDataBuilder,
       noSuchMethodRegistry,
       customElementsResolutionAnalysis,
       lookupMapResolutionAnalysis,
       mirrorsResolutionAnalysis,
       new TypeVariableResolutionAnalysis(
           elementEnvironment, impacts, backendUsageBuilder),
       nativeResolutionEnqueuer,
       deferredLoadTask);
 }
 
 ClosedWorld computeClosedWorld(Compiler compiler, ResolutionEnqueuer enqueuer) {
   enqueuer.open(const ImpactStrategy(), compiler.mainFunction,
       compiler.libraryLoader.libraries);
   enqueuer.forEach((work) {
     MemberElement element = work.element;
     ResolutionImpact resolutionImpact = build(compiler, element.resolvedAst);
     WorldImpact worldImpact = compiler.backend.impactTransformer
         .transformResolutionImpact(enqueuer, resolutionImpact);
     enqueuer.applyImpact(worldImpact, impactSource: element);
   });
   return enqueuer.worldBuilder.closeWorld(compiler.reporter);
 }