Move assets into lib/src.

lib/src/barback/foreign_transformer.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 pub.foreign_transformer;
 
 import 'dart:async';
 import 'dart:isolate';
 
 import 'package:barback/barback.dart';
 
-import '../../../asset/dart/serialize.dart';
+import '../asset/dart/serialize.dart';
 import 'excluding_transformer.dart';
 import 'excluding_aggregate_transformer.dart';
 import 'transformer_config.dart';
 
 /// A wrapper for a transformer that's in a different isolate.
 class _ForeignTransformer extends Transformer {
   /// The port with which we communicate with the child isolate.
   ///
   /// This port and all messages sent across it are specific to this
   /// transformer.
@@ skipping 138 matching lines @@
     default: assert(false);
   }
 
   if (transformer is Transformer) {
     return ExcludingTransformer.wrap(transformer, config);
   } else {
     assert(transformer is AggregateTransformer);
     return ExcludingAggregateTransformer.wrap(transformer, config);
   }
 }