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

runtime/bin/stream_util.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.
 
 class _BaseDataInputStream {
   abstract int available();
 
   List<int> read([int len]) {
     if (_closeCallbackCalled) return null;
     int bytesToRead = available();
@@ skipping 39 matching lines @@
 
   void set onClosed(void callback()) {
     _clientCloseHandler = callback;
     _checkScheduleCallbacks();
   }
 
   void set onError(void callback(e)) {
     _clientErrorHandler = callback;
   }
 
+  void _reportError(e) {
+    if (_clientErrorHandler != null) {
+      _clientErrorHandler(e);
+    } else {
+      throw e;
+    }
+  }
+
   abstract List<int> _read(int bytesToRead);
 
   void _dataReceived() {
     // More data has been received asynchronously. Perform the data
     // handler callback now.
     _cancelScheduledDataCallback();
     if (_clientDataHandler !== null) {
       _clientDataHandler();
     }
     _checkScheduleCallbacks();
@@ skipping 124 matching lines @@
   void _reportError(e) {
     if (_onError != null) {
       _onError(e);
     } else {
       throw e;
     }
   }
 
   Function _onError;
 }