Refinements for asynchronous rendering in wp.mce.media.PlaylistView:

* Add `visibility: hidden` as an inline style to `<audio>` tags, there is a race with the stylesheet which can get enqueued in the body and loaded in the footer.
* When creating new instances of `MediaElementPlayer`, always push them onto a stack. Lone views can be responsible for multiple instances of the same shortcode on render.
* Rename `wp.media.mixin.unsetPlayer()` to `wp.media.mixin.unsetPlayers()` to reflect the above.
* Call `wp.media.mixin.unsetPlayers()` on the view's `unbind()` method, instead of inline in the `render()` method
* Make sure `WPPlaylistView` is instantiated for each editor instance
* Ensure that the `No Items Found` view state is not rendered when attachments actually do exist.

Props gcorne, wonderboymusic.
See #27899.



Built from https://develop.svn.wordpress.org/trunk@28182


git-svn-id: http://core.svn.wordpress.org/trunk@28013 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/media-template.php

@@ -16,7 +16,8 @@
 function wp_underscore_audio_template() {
 	$audio_types = wp_get_audio_extensions();
 ?>
-<audio controls
+<audio style="visibility: hidden"
+	controls
 	class="wp-audio-shortcode"
 	width="{{ _.isUndefined( data.model.width ) ? 400 : data.model.width }}"
 	preload="{{ _.isUndefined( data.model.preload ) ? 'none' : data.model.preload }}"