Roll to pickup pool changes

packages/barback/lib/src/transformer/wrapping_aggregate_transformer.dart

 // Copyright (c) 2014, 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.transformer.wrapping_aggregate_transformer;
 
 import 'dart:async';
 
 import '../asset/asset_id.dart';
 import 'aggregate_transform.dart';
@@ skipping 42 matching lines @@
   }
 
   String toString() => transformer.toString();
 }
 
 /// A wrapper for [DeclaringTransformer]s that implements
 /// [DeclaringAggregateTransformer].
 class _DeclaringWrappingAggregateTransformer
     extends WrappingAggregateTransformer
     implements DeclaringAggregateTransformer {
-  final DeclaringTransformer _declaring;
-
   _DeclaringWrappingAggregateTransformer(DeclaringTransformer transformer)
-      : _declaring = transformer,
-        super._(transformer as Transformer);
+      : super._(transformer as Transformer);
 
   Future declareOutputs(DeclaringAggregateTransform aggregateTransform) {
     return newDeclaringTransform(aggregateTransform).then((transform) {
       return (transformer as DeclaringTransformer).declareOutputs(transform);
     });
   }
 }
 
 /// A wrapper for [LazyTransformer]s that implements
 /// [LazyAggregateTransformer].
 class _LazyWrappingAggregateTransformer
     extends _DeclaringWrappingAggregateTransformer
     implements LazyAggregateTransformer {
   _LazyWrappingAggregateTransformer(LazyTransformer transformer)
       : super(transformer);
 }