Make sure that errors are thrown when there is no error handler

runtime/bin/stream_util.dart

Index: runtime/bin/stream_util.dart
diff --git a/runtime/bin/stream_util.dart b/runtime/bin/stream_util.dart
index efc2f82411395bf042364c8deca19f56d3ba3ce0..57c68d312afdb56fd6c8bd8b9f87f8688a079d16 100644
--- a/runtime/bin/stream_util.dart
+++ b/runtime/bin/stream_util.dart
@@ -57,6 +57,14 @@ class _BaseDataInputStream {
     _clientErrorHandler = callback;
   }
 
+  void _reportError(e) {
+    if (_clientErrorHandler != null) {
+      _clientErrorHandler(e);
+    } else {
+      throw e;
+    }
+  }
+
   abstract List<int> _read(int bytesToRead);
 
   void _dataReceived() {