As in https://bugs.webkit.org/show_bug.cgi?id=47205, it needs to be added in CodeGeneratorV8.pm. However, it's not directly constructable, so it doesn't need the custom constructor. The ref() is done in wrapSlow(), which gets called via FileWriterCallback.
Created attachment 70181 [details] One-liner. Hope this works; I haven't created a patch manually on Windows before.
Comment on attachment 70181 [details] One-liner. View in context: https://bugs.webkit.org/attachment.cgi?id=70181&action=review > WebCore/ChangeLog:5 > + Add FileWriter to V8 active DOM map Please add "[V8]" prefix to the bug title and also update the ChangeLog.
Created attachment 70183 [details] Fixed ChangeLog and bug title.
Comment on attachment 70183 [details] Fixed ChangeLog and bug title. Clearing flags on attachment: 70183 Committed r69370: <http://trac.webkit.org/changeset/69370>
All reviewed patches have been landed. Closing bug.