r45812 incorrectly introduced a delete_post permissions check into the get_item method, breaking some plugins which requested revisions when generating previews. Props sorenbronsted, yohannp, TimothyBlynJacobs. Fixes #49645. git-svn-id: https://develop.svn.wordpress.org/trunk@47547 602fd350-edb4-49c9-b593-d223f7449a82