Update charted to 0.4.8 and roll

packages/async/lib/src/stream_group.dart

Index: packages/async/lib/src/stream_group.dart
diff --git a/packages/async/lib/src/stream_group.dart b/packages/async/lib/src/stream_group.dart
index d99f5151467855dc97fb3f92d804b53c21c78a6a..6361a5cb96f78bd4341dce75415d05a84c6f33e3 100644
--- a/packages/async/lib/src/stream_group.dart
+++ b/packages/async/lib/src/stream_group.dart
@@ -2,8 +2,6 @@
 // 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 async.stream_group;
-
 import 'dart:async';
 
 /// A collection of streams whose events are unified and sent through a central
@@ -14,8 +12,8 @@ import 'dart:async';
 /// this means that events emitted by broadcast streams will be dropped until
 /// [stream] has a listener.**
 ///
-/// If the `StreamGroup` is constructed using [new StreamGroup], [stream] will be
-/// single-subscription. In this case, if [stream] is paused or canceled, all
+/// If the `StreamGroup` is constructed using [new StreamGroup], [stream] will
+/// be single-subscription. In this case, if [stream] is paused or canceled, all
 /// streams in the group will likewise be paused or canceled, respectively.
 ///
 /// If the `StreamGroup` is constructed using [new StreamGroup.broadcast],
@@ -55,8 +53,8 @@ class StreamGroup<T> implements Sink<Stream<T>> {
   ///
   /// This is equivalent to adding [streams] to a group, closing that group, and
   /// returning its stream.
-  static Stream merge(Iterable<Stream> streams) {
-    var group = new StreamGroup();
+  static Stream<T> merge<T>(Iterable<Stream<T>> streams) {
+    var group = new StreamGroup<T>();
     streams.forEach(group.add);
     group.close();
     return group.stream;
@@ -75,9 +73,7 @@ class StreamGroup<T> implements Sink<Stream<T>> {
   /// Creates a new stream group where [stream] is a broadcast stream.
   StreamGroup.broadcast() {
     _controller = new StreamController<T>.broadcast(
-        onListen: _onListen,
-        onCancel: _onCancelBroadcast,
-        sync: true);
+        onListen: _onListen, onCancel: _onCancelBroadcast, sync: true);
   }
 
   /// Adds [stream] as a member of this group.
@@ -194,11 +190,9 @@ class StreamGroup<T> implements Sink<Stream<T>> {
   /// Starts actively forwarding events from [stream] to [_controller].
   ///
   /// This will pause the resulting subscription if [this] is paused.
-  StreamSubscription _listenToStream(Stream stream) {
-    var subscription = stream.listen(
-        _controller.add,
-        onError: _controller.addError,
-        onDone: () => remove(stream));
+  StreamSubscription<T> _listenToStream(Stream<T> stream) {
+    var subscription = stream.listen(_controller.add,
+        onError: _controller.addError, onDone: () => remove(stream));
     if (_state == _StreamGroupState.paused) subscription.pause();
     return subscription;
   }