Add stub versions of KernelInferrerEngine and friends

pkg/compiler/lib/src/js_backend/element_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_backend.element_strategy;
 
 import '../backend_strategy.dart';
 import '../closure.dart' show ClosureConversionTask, ClosureTask;
 import '../common.dart';
 import '../common/codegen.dart';
 import '../common/tasks.dart';
 import '../common/work.dart';
 import '../compiler.dart';
 import '../elements/elements.dart';
 import '../enqueue.dart';
+import '../inferrer/type_graph_inferrer.dart' show AstTypeGraphInferrer;
 import '../io/multi_information.dart' show MultiSourceInformationStrategy;
 import '../io/position_information.dart' show PositionSourceInformationStrategy;
 import '../io/source_information.dart';
 import '../io/start_end_information.dart'
     show StartEndSourceInformationStrategy;
 import '../js/js_source_mapping.dart' show JavaScriptSourceInformationStrategy;
 import '../js_backend/backend.dart';
 import '../js_backend/native_data.dart';
 import '../js_emitter/sorter.dart';
 import '../resolution/resolution_strategy.dart';
 import '../ssa/builder.dart';
 import '../ssa/rasta_ssa_builder_task.dart';
 import '../ssa/ssa.dart';
+import '../types/types.dart';
 import '../options.dart';
 import '../universe/world_builder.dart';
 import '../universe/world_impact.dart';
 import '../world.dart';
 
 /// Strategy for using the [Element] model from the resolver as the backend
 /// model.
 class ElementBackendStrategy extends ComputeSpannableMixin
     implements BackendStrategy {
   final Compiler _compiler;
@@ skipping 59 matching lines @@
           const StartEndSourceInformationStrategy(),
           const PositionSourceInformationStrategy()
         ]);
       }
     } else if (useNewSourceInfo) {
       return const PositionSourceInformationStrategy();
     } else {
       return const StartEndSourceInformationStrategy();
     }
   }
+
+  @override
+  GlobalTypeInferenceResults createTypesInferrerResults(
+      TypesInferrer typesInferrer, ClosedWorld closedWorld) {
+    return new AstGlobalTypeInferenceResults(typesInferrer, closedWorld);
+  }
+
+  @override
+  TypesInferrer createTypesInferrer(ClosedWorldRefiner closedWorldRefiner,
+      {bool disableTypeInference: false}) {
+    return new AstTypeGraphInferrer(
+        _compiler, closedWorldRefiner.closedWorld, closedWorldRefiner,
+        disableTypeInference: disableTypeInference);
+  }
 }
 
 /// Builder that creates the work item necessary for the code generation of a
 /// [MemberElement].
 class ElementCodegenWorkItemBuilder extends WorkItemBuilder {
   final JavaScriptBackend _backend;
   final ClosedWorld _closedWorld;
   final CompilerOptions _options;
 
   ElementCodegenWorkItemBuilder(
@@ skipping 42 matching lines @@
 
   MemberElement get element => resolvedAst.element;
 
   WorldImpact run() {
     registry = new CodegenRegistry(_closedWorld.elementEnvironment, element);
     return _backend.codegen(this, _closedWorld);
   }
 
   String toString() => 'CodegenWorkItem(${resolvedAst.element})';
 }