r224280 introduced operationToObject() with an option to specify a custom error message. r254252 added a scenario where the passed in error message is null but did not fix operationToObject() to allow for this. We should add the missing null check. <rdar://problem/58449666>
Created attachment 387897 [details] proposed patch.
Comment on attachment 387897 [details] proposed patch. r=me
Thanks for the review. Landed in r254687: <http://trac.webkit.org/r254687>.