Regenerate pub sources.

sdk/lib/_internal/pub_generated/lib/src/barback/dart_forwarding_transformer.dart

Index: sdk/lib/_internal/pub_generated/lib/src/barback/dart_forwarding_transformer.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/barback/dart_forwarding_transformer.dart b/sdk/lib/_internal/pub_generated/lib/src/barback/dart_forwarding_transformer.dart
index af8aea2613c70440d05d400c6e4b62e66d5e1721..d1129248f483490ba159cec7f9a9e429d43ae830 100644
--- a/sdk/lib/_internal/pub_generated/lib/src/barback/dart_forwarding_transformer.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/barback/dart_forwarding_transformer.dart
@@ -1,11 +1,29 @@
+// 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.dart_forwarding_transformer;
+
 import 'dart:async';
+
 import 'package:barback/barback.dart';
+
 import '../utils.dart';
+
+/// A single transformer that just forwards any ".dart" file as an output when
+/// not in release mode.
+///
+/// Since the [Dart2JSTransformer] consumes its inputs, this is used in
+/// parallel to make sure the original Dart file is still available for use by
+/// Dartium.
 class DartForwardingTransformer extends Transformer {
+  /// The mode that the transformer is running in.
   final BarbackMode _mode;
+
   DartForwardingTransformer(this._mode);
+
   String get allowedExtensions => ".dart";
+
   Future apply(Transform transform) {
     return newFuture(() {
       transform.addOutput(transform.primaryInput);