| Index: Source/core/dom/MutationObserver.idl | 
| diff --git a/Source/core/dom/MutationObserver.idl b/Source/core/dom/MutationObserver.idl | 
| index 29aa06e7f1f71f6abd27feca3f0a8af36e3d6cdb..6df62b70e5f162f5dbff59a5a1fd70e5823f2df4 100644 | 
| --- a/Source/core/dom/MutationObserver.idl | 
| +++ b/Source/core/dom/MutationObserver.idl | 
| @@ -29,7 +29,7 @@ | 
| */ | 
|  | 
| [ | 
| -    CustomConstructor, | 
| +    CustomConstructor(MutationCallback callback), | 
| ImplementationLacksVTable | 
| ] interface MutationObserver { | 
| [RaisesException] void observe(Node target, Dictionary options); | 
|  |