Cleanup after [29179]:

* Pause players when media is edited via modal
* Remove players on unind
* Account for failure when an empty node is passed to an `mce.view.View`

See #28905.

Built from https://develop.svn.wordpress.org/trunk@29191


git-svn-id: http://core.svn.wordpress.org/trunk@28975 1a063a9b-81f0-0310-95a4-ce76da25c4cd