fixes #27477. Built from https://develop.svn.wordpress.org/trunk@27651 git-svn-id: http://core.svn.wordpress.org/trunk@27494 1a063a9b-81f0-0310-95a4-ce76da25c4cd
props mcsf, ehg, gcorne. see #21785. Built from https://develop.svn.wordpress.org/trunk@27497 git-svn-id: http://core.svn.wordpress.org/trunk@27339 1a063a9b-81f0-0310-95a4-ce76da25c4cd