Reduce use of elements/resolution_types in enqueuer.

tests/compiler/dart2js/resolver_test.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.
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'package:compiler/src/constants/expressions.dart';
@@ skipping 1132 matching lines @@
   Uri uri = new Uri(scheme: 'source');
   MockCompiler compiler = compilerFor(source, uri);
   compiler.diagnosticHandler = createHandler(compiler, source);
   return compiler.run(uri).then((_) {
     return compiler;
   });
 }
 
 checkMemberResolved(compiler, className, memberName) {
   ClassElement cls = findElement(compiler, className);
-  Element memberElement = cls.lookupLocalMember(memberName);
+  MemberElement memberElement = cls.lookupLocalMember(memberName);
   Expect.isNotNull(memberElement);
-  Expect.isTrue(compiler.enqueuer.resolution.hasBeenProcessed(memberElement));
+  Expect.isTrue(compiler.resolutionWorldBuilder.isMemberUsed(memberElement));
 }
 
 testToString() {
   final script = r"class C { toString() => 'C'; } main() { '${new C()}'; }";
   asyncTest(() => compileScript(script).then((compiler) {
         checkMemberResolved(compiler, 'C', 'toString');
       }));
 }
 
 operatorName(op, isUnary) {
@@ skipping 372 matching lines @@
       functionName: 'm');
   check(
       '''
     class A {
       m() => () => await - 3;
     }
     main() => new A().m();
   ''',
       className: 'A');
 }