| Index: tool/input_sdk/patch/internal_patch.dart
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| diff --git a/tool/input_sdk/patch/internal_patch.dart b/tool/input_sdk/patch/internal_patch.dart
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| index 16afd5f3aa6332ec62190bdf31b5ff3455f4f898..f5bce774f35fbb72748a630b3e7d085a717f5372 100644
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| --- a/tool/input_sdk/patch/internal_patch.dart
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| +++ b/tool/input_sdk/patch/internal_patch.dart
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| @@ -23,3 +23,9 @@ List makeListFixedLength(List growableList) {
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|    JSArray.markFixedList(growableList);
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|    return growableList;
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|  }
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| +
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| +@patch
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| +List makeFixedListUnmodifiable(List list) {
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| +  JSArray.markUnmodifiableList(list);
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| +  return list;
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| +}
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| 
 |