Reduce use of elements/resolution_types in enqueuer.

pkg/compiler/lib/src/compiler.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.compiler_base;
 
 import 'dart:async' show EventSink, Future;
 
 import '../compiler_new.dart' as api;
 import 'closure.dart' as closureMapping show ClosureTask;
@@ skipping 926 matching lines @@
     }
     return element;
   }
 
   bool get isMockCompilation => false;
 
   void reportUnusedCode() {
     void checkLive(member) {
       if (member.isMalformed) return;
       if (member.isFunction) {
-        if (!enqueuer.resolution.hasBeenProcessed(member)) {
+        if (!resolutionWorldBuilder.isMemberUsed(member)) {
           reporter.reportHintMessage(
               member, MessageKind.UNUSED_METHOD, {'name': member.name});
         }
       } else if (member.isClass) {
         if (!member.isResolved) {
           reporter.reportHintMessage(
               member, MessageKind.UNUSED_CLASS, {'name': member.name});
         } else {
           member.forEachLocalMember(checkLive);
         }
@@ skipping 1079 matching lines @@
     if (library != null && library.isSynthesized) {
       return null;
     }
     if (library == null && required) {
       throw new SpannableAssertionFailure(
           library, "The library '${uri}' was not found.");
     }
     return library;
   }
 }