reddit/reddit — pull request #1065 by JordanMilne (2014-06-10 14:23:49+00:00)
Title: /widget: Use an acceptable callback for the .embed preview

Should partially fix the issue described in http://www.reddit.com/r/bugs/comments/2779mt/widget_pages_reloading_and_display_404_or_400/ where the callback was getting rejected and always returning `400`.