Expand ResolvedAst to handle synthetic constructors.

tests/compiler/dart2js/analyze_dart2js_helpers_test.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.analyze_helpers.test;
 
 import 'dart:io';
 
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/compiler_new.dart' show
@@ skipping 76 matching lines @@
   AnalyzableElement get analyzedElement => resolvedAst.element;
 
   HelperAnalyzer(this.diagnostics) : super(null);
 
   @override
   void apply(Node node, [_]) {
     node.accept(this);
   }
 
   void analyze(ResolvedAst resolvedAst) {
-    if (resolvedAst.node == null) {
+    if (resolvedAst.kind != ResolvedAstKind.PARSED) {
       // Skip synthesized members.
       return;
     }
     this.resolvedAst = resolvedAst;
     apply(resolvedAst.node);
     this.resolvedAst = null;
   }
 
   bool isHelper(Element element) {
     Uri uri = element.library.canonicalUri;
@@ skipping 119 matching lines @@
   }
 
   @override
   void visitConstConstructorInvoke(
       NewExpression node,
       ConstructedConstantExpression constant,
       _) {
     checkAccess(node, constant.target);
   }
 }