Further reduce use of Element in codegen.

pkg/compiler/lib/src/universe/selector.dart

 // Copyright (c) 2015, 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.selector;
 
 import '../common.dart';
 import '../common/names.dart' show Names;
 import '../elements/elements.dart'
     show
         Element,
         Elements,
         FunctionElement,
         FunctionSignature,
+        MemberElement,
         Name,
         LibraryElement,
         PublicName;
 import '../util/util.dart' show Hashing;
 import '../common/resolution.dart' show Target;
 import 'call_structure.dart' show CallStructure;
 
 class SelectorKind {
   final String name;
   final int hashCode;
@@ skipping 215 matching lines @@
     if (isGetter) return true;
     if (isSetter) return false;
     return signatureApplies(element);
   }
 
   bool signatureApplies(FunctionElement function) {
     if (Elements.isUnresolved(function)) return false;
     return callStructure.signatureApplies(function.functionSignature);
   }
 
-  bool applies(Element element) {
+  bool applies(MemberElement element) {
     if (name != element.name) return false;
     return appliesUnnamed(element);
   }
 
   bool match(SelectorKind kind, Name memberName, CallStructure callStructure) {
     return this.kind == kind &&
         this.memberName == memberName &&
         this.callStructure.match(callStructure);
   }
 
   static int computeHashCode(
       SelectorKind kind, Name name, CallStructure callStructure) {
     // Add bits from name and kind.
     int hash = Hashing.mixHashCodeBits(name.hashCode, kind.hashCode);
     // Add bits from the call structure.
     return Hashing.mixHashCodeBits(hash, callStructure.hashCode);
   }
 
   String toString() {
     return 'Selector($kind, $name, ${callStructure.structureToString()})';
   }
 
   Selector toCallSelector() => new Selector.callClosureFrom(this);
 }