Move ElementEnvironment.isSubtype to DartTypes

pkg/compiler/lib/src/resolution/resolution_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.resolution_strategy;
 
 import '../common.dart';
 import '../common_elements.dart';
 import '../common/backend_api.dart';
 import '../common/names.dart';
 import '../common/resolution.dart';
 import '../common/tasks.dart';
 import '../common/work.dart';
 import '../compiler.dart';
 import '../constants/values.dart';
 import '../elements/elements.dart';
 import '../elements/entities.dart';
 import '../elements/modelx.dart';
 import '../elements/resolution_types.dart';
+import '../elements/types.dart';
 import '../environment.dart';
 import '../enqueue.dart';
 import '../frontend_strategy.dart';
 import '../js_backend/backend.dart';
 import '../js_backend/backend_usage.dart';
 import '../js_backend/custom_elements_analysis.dart';
 import '../js_backend/interceptor_data.dart';
 import '../js_backend/mirrors_analysis.dart';
 import '../js_backend/mirrors_data.dart';
 import '../js_backend/native_data.dart';
@@ skipping 12 matching lines @@
 /// [FrontendStrategy] that loads '.dart' files and creates a resolved element
 /// model using the resolver.
 class ResolutionFrontEndStrategy implements FrontEndStrategy {
   final Compiler _compiler;
   final ElementEnvironment elementEnvironment;
   AnnotationProcessor _annotationProcessor;
 
   ResolutionFrontEndStrategy(this._compiler)
       : elementEnvironment = new _CompilerElementEnvironment(_compiler);
 
+  DartTypes get dartTypes => _compiler.types;
+
   LibraryLoaderTask createLibraryLoader(
       ResolvedUriTranslator uriTranslator,
       ScriptLoader scriptLoader,
       ElementScanner scriptScanner,
       LibraryDeserializer deserializer,
       PatchResolverFunction patchResolverFunc,
       PatchParserTask patchParser,
       Environment environment,
       DiagnosticReporter reporter,
       Measurer measurer) {
@@ skipping 188 matching lines @@
   }
 
   @override
   ResolutionInterfaceType createInterfaceType(
       ClassElement cls, List<ResolutionDartType> typeArguments) {
     cls.ensureResolved(_resolution);
     return cls.thisType.createInstantiation(typeArguments);
   }
 
   @override
-  bool isSubtype(ResolutionDartType a, ResolutionDartType b) {
-    return _compiler.types.isSubtype(a, b);
-  }
-
-  @override
   MemberElement lookupClassMember(ClassElement cls, String name,
       {bool setter: false, bool required: false}) {
     cls.ensureResolved(_resolution);
     Element member = cls.implementation.lookupLocalMember(name);
     if (member != null && member.isAbstractField) {
       AbstractFieldElement abstractField = member;
       if (setter) {
         member = abstractField.setter;
       } else {
         member = abstractField.getter;
@@ skipping 387 matching lines @@
   @override
   WorkItem createWorkItem(MemberElement element) {
     assert(invariant(element, element.isDeclaration));
     if (element.isMalformed) return null;
 
     assert(invariant(element, element is AnalyzableElement,
         message: 'Element $element is not analyzable.'));
     return _resolution.createWorkItem(element);
   }
 }