Rename unsubscribe to cancel.

tests/lib/async/event_helper.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 event_helper;
 
 import 'dart:async';
 
 class Event {
   void replay(StreamSink sink);
@@ skipping 123 matching lines @@
 
 class CaptureEvents extends Events {
   StreamSubscription subscription;
   SignalCompleter onDoneSignal;
   bool unsubscribeOnError = false;
 
   CaptureEvents(Stream stream,
                 { bool unsubscribeOnError: false })
       : onDoneSignal = new SignalCompleter() {
     this.unsubscribeOnError = unsubscribeOnError;
-    subscription = stream.subscribe(onData: add,
-                                    onError: signalError,
-                                    onDone: close,
-                                    unsubscribeOnError: unsubscribeOnError);
+    subscription = stream.listen(add,
+                                 onError: signalError,
+                                 onDone: close,
+                                 unsubscribeOnError: unsubscribeOnError);
   }
 
   void signalError(AsyncError error) {
     super.signalError(error);
     if (unsubscribeOnError) onDoneSignal.complete();
   }
 
   void close() {
     super.close();
     if (onDoneSignal != null) onDoneSignal.complete();
   }
 
   void pause([Signal resumeSignal]) {
     subscription.pause(resumeSignal);
   }
 
   void resume() {
     subscription.resume();
   }
 
   bool get isPaused => subscription.isPaused;
 
   void onDone(void action()) {
     onDoneSignal.signal.then(action);
   }
 }