Remove calls to [new Future] work around issue 11911.

pkg/barback/test/utils.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 barback.test.utils;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:io';
 
@@ skipping 498 matching lines @@
   /// The error it throws.
   static const ERROR = "I am a bad transformer!";
 
   /// The list of asset names that it should output.
   final List<String> outputs;
 
   BadTransformer(this.outputs);
 
   Future<bool> isPrimary(Asset asset) => new Future.value(true);
   Future apply(Transform transform) {
-    return new Future(() {
+    return newFuture(() {
       // Create the outputs first.
       for (var output in outputs) {
         var id = new AssetId.parse(output);
         transform.addOutput(new MockAsset(id, output));
       }
 
       // Then fail.
       throw ERROR;
     });
   }
 }
 
 /// A transformer that outputs an asset with the given id.
 class CreateAssetTransformer extends Transformer {
   final String output;
 
   CreateAssetTransformer(this.output);
 
   Future<bool> isPrimary(Asset asset) => new Future.value(true);
 
   Future apply(Transform transform) {
-    return new Future(() {
+    return newFuture(() {
       transform.addOutput(new MockAsset(new AssetId.parse(output), output));
     });
   }
 }
 
 /// An implementation of [Asset] that never hits the file system.
 class MockAsset implements Asset {
   final AssetId id;
   String contents;
 
   MockAsset(this.id, this.contents);
 
   Future<String> readAsString({Encoding encoding}) =>
       new Future.value(contents);
 
   Stream<List<int>> read() => throw new UnimplementedError();
 
   String toString() => "MockAsset $id $contents";
 }