Bug 1509989 - Make sure that CutContents doesn't remove nodes that isn't supposed to remove. r=mats

Depends on D13071

Differential Revision: https://phabricator.services.mozilla.com/D13072

--HG--
extra : moz-landing-system : lando

dom/base/nsRange.cpp

@@ -1977,6 +1977,10 @@ nsRange::CutContents(DocumentFragment** aFragment)
     *aFragment = nullptr;
   }
 
+  if (!CanAccess(*mStart.Container()) || !CanAccess(*mEnd.Container())) {
+    return NS_ERROR_DOM_SECURITY_ERR;
+  }
+
   nsCOMPtr<nsIDocument> doc = mStart.Container()->OwnerDoc();
 
   ErrorResult res;