Use entities in code_emitter_task

pkg/compiler/lib/src/js_emitter/native_emitter.dart

 // Copyright (c) 2012, 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_emitter.native_emitter;
 
 import '../common.dart';
 import '../compiler.dart' show Compiler;
 import '../elements/resolution_types.dart'
     show ResolutionDartType, ResolutionFunctionType;
 import '../elements/elements.dart'
     show
         ClassElement,
         Element,
         FunctionElement,
         FunctionSignature,
+        MethodElement,
         ParameterElement;
 import '../js/js.dart' as jsAst;
 import '../js/js.dart' show js;
 import '../js_backend/backend_helpers.dart' show BackendHelpers;
 import '../js_backend/js_backend.dart' show JavaScriptBackend;
 import 'full_emitter/emitter.dart' as full_js_emitter;
 
 import 'code_emitter_task.dart' show CodeEmitterTask;
 import 'model.dart';
 
@@ skipping 241 matching lines @@
     return cls.methods.isEmpty &&
         cls.isChecks.isEmpty &&
         cls.callStubs.isEmpty &&
         !cls.superclass.isMixinApplication &&
         !cls.fields.any(needsAccessor);
   }
 
   void potentiallyConvertDartClosuresToJs(List<jsAst.Statement> statements,
       FunctionElement member, List<jsAst.Parameter> stubParameters) {
     FunctionSignature parameters = member.functionSignature;
-    Element converter = helpers.closureConverter;
+    MethodElement converter = helpers.closureConverter;
     jsAst.Expression closureConverter =
         emitterTask.staticFunctionAccess(converter);
     parameters.forEachParameter((ParameterElement parameter) {
       String name = parameter.name;
       // If [name] is not in [stubParameters], then the parameter is an optional
       // parameter that was not provided for this stub.
       for (jsAst.Parameter stubParameter in stubParameters) {
         if (stubParameter.name == name) {
           ResolutionDartType type = parameter.type.unaliased;
           if (type is ResolutionFunctionType) {
@@ skipping 81 matching lines @@
     // used.  We should also use an interceptor if the check can't be satisfied
     // by a native class in case we get a native instance that tries to spoof
     // the type info.  i.e the criteria for whether or not to use an interceptor
     // is whether the receiver can be native, not the type of the test.
     if (element == null || !element.isClass) return false;
     ClassElement cls = element;
     if (backend.isNativeOrExtendsNative(cls)) return true;
     return isSupertypeOfNativeClass(element);
   }
 }