| Index: sdk/lib/async/stream_impl.dart
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| diff --git a/sdk/lib/async/stream_impl.dart b/sdk/lib/async/stream_impl.dart
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| index 85aa0833b6f0233cf7399ffb256e21aee5261169..108e42b7d7dd50fa54f1e6d4a9f5b9e86ebd6f52 100644
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| --- a/sdk/lib/async/stream_impl.dart
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| +++ b/sdk/lib/async/stream_impl.dart
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| @@ -719,8 +719,11 @@ class _AsBroadcastStream<T> extends Stream<T> {
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|                                       onError: _controller.addError,
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|                                       onDone: _controller.close);
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|      }
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| -    return _controller.stream.listen(onData, onError: onError, onDone: onDone,
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| -                                     cancelOnError: cancelOnError);
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| +    if (onData == null) onData = _nullDataHandler;
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| +    if (onError == null) onError = _nullErrorHandler;
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| +    if (onDone == null) onDone = _nullDoneHandler;
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| +    cancelOnError = identical(true, cancelOnError);
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| +    return _controller._subscribe(onData, onError, onDone, cancelOnError);
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|    }
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|  
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|    void _onCancel() {
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| 
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