Make StreamController's unnamed constructor create a single-sub stream.

pkg/http/lib/src/utils.dart

 // Copyright (c) 2012, 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 utils;
 
 import 'dart:async';
 import 'dart:crypto';
 import 'dart:io';
 import 'dart:scalarlist';
@@ skipping 137 matching lines @@
   pair.first.listen((_) {}, onError: (_) {}, onDone: onDone);
   return pair.last;
 }
 
 // TODO(nweiz): remove this once issue 7785 is fixed.
 /// Wraps [stream] in a single-subscription [ByteStream] that emits the same
 /// data.
 ByteStream wrapInputStream(InputStream stream) {
   if (stream.closed) return emptyStream;
 
-  var controller = new StreamController.singleSubscription();
+  var controller = new StreamController();
   stream.onClosed = controller.close;
   stream.onData = () => controller.add(stream.read());
   stream.onError = (e) => controller.signalError(new AsyncError(e));
   return new ByteStream(controller);
 }
 
 // TODO(nweiz): remove this once issue 7785 is fixed.
 /// Wraps [stream] in a [StreamConsumer] so that [Stream]s can by piped into it
 /// using [Stream.pipe].
 StreamConsumer<List<int>, dynamic> wrapOutputStream(OutputStream stream) =>
@@ skipping 57 matching lines @@
 
 /// Returns a [Future] that asynchronously completes to `null`.
 Future get async => new Future.immediate(null);
 
 /// Returns a closed [Stream] with no elements.
 Stream get emptyStream => streamFromIterable([]);
 
 /// Creates a single-subscription stream that emits the items in [iter] and then
 /// ends.
 Stream streamFromIterable(Iterable iter) {
-  var stream = new StreamController.singleSubscription();
+  var stream = new StreamController();
   iter.forEach(stream.add);
   stream.close();
   return stream.stream;
 }
 
 // TODO(nweiz): remove this when issue 7787 is fixed.
 /// Creates two single-subscription [Stream]s that each emit all values and
 /// errors from [stream]. This is useful if [stream] is single-subscription but
 /// multiple subscribers are necessary.
 Pair<Stream, Stream> tee(Stream stream) {
-  var controller1 = new StreamController.singleSubscription();
-  var controller2 = new StreamController.singleSubscription();
+  var controller1 = new StreamController();
+  var controller2 = new StreamController();
   stream.listen((value) {
     controller1.add(value);
     controller2.add(value);
   }, onError: (error) {
     controller1.signalError(error);
     controller2.signalError(error);
   }, onDone: () {
     controller1.close();
     controller2.close();
   });
@@ skipping 34 matching lines @@
 /// The return values of all [Future]s are discarded. Any errors will cause the
 /// iteration to stop and will be piped through the return value.
 Future forEachFuture(Iterable input, Future fn(element)) {
   var iterator = input.iterator;
   Future nextElement(_) {
     if (!iterator.moveNext()) return new Future.immediate(null);
     return fn(iterator.current).then(nextElement);
   }
   return nextElement(null);
 }