Fixing type check error using Stream.take in dart2js checked mode.

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 1945bb263feb147028ac16725321baa858e494ef..1b791b57545a72d139bfb723a099be0f376fb4df 100644
--- a/sdk/lib/async/stream_pipe.dart
+++ b/sdk/lib/async/stream_pipe.dart
@@ -171,7 +171,9 @@ class _ForwardingStreamSubscription<S, T>
 
   // Methods used as listener on source subscription.
 
-  void _handleData(S data) {
+  // TODO(ahe): Restore type when feature is implemented in dart2js
+  // checked mode. http://dartbug.com/7733
+  void _handleData(/*S*/ data) {
     _stream._handleData(data, this);
   }