Make pub strong-mode clean.

lib/src/asset/dart/serialize/aggregate_transform.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.
 
 import 'dart:async';
 import 'dart:isolate';
 
 import 'package:barback/barback.dart';
 // TODO(nweiz): don't import from "src" once issue 14966 is fixed.
 import 'package:barback/src/internal_asset.dart';
 
 import '../serialize.dart';
 import 'get_input_transform.dart';
 
 /// Serialize the methods shared between [AggregateTransform] and
 /// [DeclaringAggregateTransform].
 ///
 /// [additionalFields] contains additional serialized fields to add to the
 /// serialized transform. [methodHandlers] is a set of additional methods. Each
 /// value should take a JSON message and return the response (which may be a
 /// Future).
-Map _serializeBaseAggregateTransform(transform, Map additionalFields,
+Map _serializeBaseAggregateTransform(transform,
+    Map<String, dynamic> additionalFields,
     Map<String, Function> methodHandlers) {
   var receivePort = new ReceivePort();
   receivePort.listen((wrappedMessage) {
     respond(wrappedMessage, (message) {
       var handler = methodHandlers[message['type']];
       if (handler != null) return handler(message);
 
       if (message['type'] == 'consumePrimary') {
         transform.consumePrimary(deserializeId(message['assetId']));
         return null;
@@ skipping 126 matching lines @@
             transform['primaryIds'], deserializeId),
         super(transform);
 
   void declareOutput(AssetId id) {
     call(_port, {
       'type': 'declareOutput',
       'output': serializeId(id)
     });
   }
 }