Rename unsubscribe to cancel.

sdk/lib/async/stream_pipe.dart

Index: sdk/lib/async/stream_pipe.dart
diff --git a/sdk/lib/async/stream_pipe.dart b/sdk/lib/async/stream_pipe.dart
index 2e2269a663ba1310b682af64548fa0b8d088a5fb..1215194e6bd240031d4d5ec2d47ff4a2de2951db 100644
--- a/sdk/lib/async/stream_pipe.dart
+++ b/sdk/lib/async/stream_pipe.dart
@@ -27,9 +27,9 @@ abstract class _ForwardingStream<S, T> extends _MultiStreamImpl<T>
   }
 
   void _subscribeToSource() {
-    _subscription = _source.subscribe(onData: this._handleData,
-                                      onError: this._handleError,
-                                      onDone: this._handleDone);
+    _subscription = _source.listen(this._handleData,
+                                   onError: this._handleError,
+                                   onDone: this._handleDone);
     if (_isPaused) {
       _subscription.pause();
     }
@@ -56,7 +56,7 @@ abstract class _ForwardingStream<S, T> extends _MultiStreamImpl<T>
       }
     } else {
       if (_subscription != null) {
-        _subscription.unsubscribe();
+        _subscription.cancel();
         _subscription = null;
       }
     }