Make StreamController take on{Pause,Subscription]StateChange as arguments.

tests/lib/async/slow_consumer_test.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.
 
 // VMOptions=--old_gen_heap_size=32
 
 library slow_consumer_test;
 
 import 'dart:async';
 import 'dart:isolate';
@@ skipping 23 matching lines @@
               // Make sure we use data here to keep tracking it.
               return count + data.length;
             });
           });
         },
       onDone: () { current.then((count) { completer.complete(count); }); });
     return completer.future;
   }
 }
 
-class DataProvider extends StreamController {
+class DataProvider {
   final int chunkSize;
   final int bytesPerSecond;
   int sentCount = 0;
   int targetCount;
+  StreamController controller;
 
   DataProvider(int this.bytesPerSecond, int this.targetCount, this.chunkSize) {
+    controller = new StreamController(onPauseStateChange: onPauseStateChange);
     new Timer(0, (_) => send());
   }
 
+  Stream get stream => controller.stream;
+
   send() {
-    if (isPaused) return;
+    if (controller.isPaused) return;
     if (sentCount == targetCount) {
-      close();
+      controller.close();
       return;
     }
     int listSize = chunkSize;
     sentCount += listSize;
     if (sentCount > targetCount) {
       listSize -= sentCount - targetCount;
       sentCount = targetCount;
     }
-    add(new List.fixedLength(listSize));
+    controller.add(new List.fixedLength(listSize));
     int ms = listSize * 1000 ~/ bytesPerSecond;
-    if (!isPaused) new Timer(ms, (_) => send());
+    if (!controller.isPaused) new Timer(ms, (_) => send());
   }
 
   onPauseStateChange() {
     // We don't care if we just unpaused or paused. In either case we just
     // call send which will test it for us.
     send();
   }
 }
 
 main() {
   var port = new ReceivePort();
   // The data provider can deliver 800MB/s of data. It sends 100MB of data to
   // the slower consumer who can only read 200MB/s. The data is sent in 1MB
   // chunks.
   //
   // This test is limited to 32MB of heap-space (see VMOptions on top of the
   // file). If the consumer doesn't pause the data-provider it will run out of
   // heap-space.
 
-  new DataProvider(800 * MB, 100 * MB, 1 * MB)
+  new DataProvider(800 * MB, 100 * MB, 1 * MB).stream
     .pipe(new SlowConsumer(200 * MB))
     .then((count) {
       port.close();
       Expect.equals(100 * MB, count);
     });
 }