Revert "Towards compiling Hello World!" and "Compile and run Hello World!"

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_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/kernel_strategy.dart';
 import '../kernel/kernel_backend_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 {
   final Compiler _compiler;
@@ skipping 94 matching lines @@
   @override
   WorkItemBuilder createCodegenWorkItemBuilder(ClosedWorld closedWorld) {
     return new KernelCodegenWorkItemBuilder(_compiler.backend, closedWorld);
   }
 
   @override
   CodegenWorldBuilder createCodegenWorldBuilder(
       NativeBasicData nativeBasicData,
       ClosedWorld closedWorld,
       SelectorConstraintsStrategy selectorConstraintsStrategy) {
-    KernelFrontEndStrategy frontendStrategy = _compiler.frontendStrategy;
-    return new KernelCodegenWorldBuilder(
-        frontendStrategy.elementMap,
-        closedWorld.elementEnvironment,
-        nativeBasicData,
-        closedWorld,
-        selectorConstraintsStrategy);
+    return new KernelCodegenWorldBuilder(closedWorld.elementEnvironment,
+        nativeBasicData, closedWorld, selectorConstraintsStrategy);
   }
 }