Remove deprecated parts of dart:async.

pkg/polymer/test/build/common.dart

 // Copyright (c) 2013, 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 polymer.test.build.common;
 
 import 'dart:async';
 
 import 'package:barback/barback.dart';
 import 'package:stack_trace/stack_trace.dart';
@@ skipping 28 matching lines @@
   Future<Asset> getAsset(AssetId id) =>
       new Future.value(new Asset.fromString(id, files[idToString(id)]));
   TestHelper(List<List<Transformer>> transformers, Map<String, String> files)
       : files = files,
         packages = files.keys.map((s) => idFromString(s).package) {
     barback = new Barback(this);
     for (var p in packages) {
       barback.updateTransformers(p, transformers);
     }
     errorSubscription = barback.errors.listen((e) {
-      var trace = getAttachedStackTrace(e);
+      var trace = null;
+      if (e is Error) trace = e.stackTrace;
       if (trace != null) {
         print(Trace.format(trace));
       }
       fail('error running barback: $e');
     });
     resultSubscription = barback.results.listen((result) {
       expect(result.succeeded, isTrue, reason: "${result.errors}");
     });
   }
 
@@ skipping 44 matching lines @@
 // TODO(jmesserly): this is .debug to workaround issue 13046.
 const SHADOW_DOM_TAG =
     '<script src="packages/shadow_dom/shadow_dom.debug.js"></script>\n';
 
 const INTEROP_TAG = '<script src="packages/browser/interop.js"></script>\n';
 const DART_JS_TAG = '<script src="packages/browser/dart.js"></script>';
 
 const CUSTOM_ELEMENT_TAG =
     '<script src="packages/custom_element/custom-elements.debug.js">'
     '</script>\n';