Further reduce use of Element in codegen.

pkg/compiler/lib/src/common/resolution.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.common.resolution;
 
 import '../common.dart';
 import '../compile_time_constants.dart';
 import '../compiler.dart' show Compiler;
 import '../constants/expressions.dart' show ConstantExpression;
 import '../constants/values.dart' show ConstantValue;
 import '../core_types.dart' show CommonElements;
 import '../dart_types.dart' show DartType, Types;
 import '../elements/elements.dart'
     show
         AstElement,
         ClassElement,
         Element,
+        Entity,
         ExecutableElement,
         FunctionElement,
         FunctionSignature,
         LibraryElement,
         MetadataAnnotation,
         MethodElement,
         ResolvedAst,
         TypedefElement;
 import '../enqueue.dart' show ResolutionEnqueuer;
 import '../id_generator.dart';
@@ skipping 76 matching lines @@
 
   /// Returns `true` if [element] is a default implementation of `noSuchMethod`
   /// used by the target.
   bool isDefaultNoSuchMethod(MethodElement element);
 
   /// Returns the default superclass for the given [element] in this target.
   ClassElement defaultSuperclass(ClassElement element);
 
   /// Returns `true` if [element] is a native element, that is, that the
   /// corresponding entity already exists in the target language.
-  bool isNative(Element element) => false;
+  bool isNative(Entity element) => false;
 
   /// Returns `true` if [element] is a foreign element, that is, that the
   /// backend has specialized handling for the element.
   bool isForeign(Element element) => false;
 
   /// Returns `true` if this target supports async/await.
   bool get supportsAsyncAwait => true;
 }
 
 // TODO(johnniwinther): Rename to `Resolver` or `ResolverContext`.
@@ skipping 123 matching lines @@
       if (cls.isPatch) {
         patchParser.parsePatchClassNode(cls);
       }
     });
   }
 
   @override
   ScannerOptions getScannerOptionsFor(Element element) => new ScannerOptions(
       canUseNative: backend.canLibraryUseNative(element.library));
 }