Because it complicates things.
Created attachment 214085 [details] proposed patch
Comment on attachment 214085 [details] proposed patch Ryosuke, could you please deploy this once it lands? Looks like unit tests that this code has can only be run on appspot, not locally.
Comment on attachment 214085 [details] proposed patch Clearing flags on attachment: 214085 Committed r157359: <http://trac.webkit.org/changeset/157359>
All reviewed patches have been landed. Closing bug.