Renamed StreamSink to EventSink. Renamed signalError to addError.

utils/pub/error_group.dart

Index: utils/pub/error_group.dart
diff --git a/utils/pub/error_group.dart b/utils/pub/error_group.dart
index 16b96b19c36dd3c1ddcb70c54e7b535e1db6c865..dc0ba8a7fce1ef46e5212b5eb8051c80d58c1775 100644
--- a/utils/pub/error_group.dart
+++ b/utils/pub/error_group.dart
@@ -272,7 +272,7 @@ class _ErrorGroupStream extends Stream {
     _subscription.cancel();
     // Call these asynchronously to work around issue 7913.
     defer(() {
-      _controller.signalError(e.error, e.stackTrace);
+      _controller.addError(e.error, e.stackTrace);
       _controller.close();
     });
   }