Ticket #29048: 29048.3.patch

src/wp-admin/includes/ajax-actions.php

@@ -2677 +2677 @@
 
         if ( has_shortcode( $parsed, 'audio' ) || has_shortcode( $parsed, 'video' ) ) {
                 $styles = '';
-                $mce_styles = wp_media_mce_styles();
+                $mce_styles = wpview_media_sandbox_styles();
                 foreach ( $mce_styles as $style ) {
                         $styles .= sprintf( '<link rel="stylesheet" href="%s"/>', $style );
                 }
@@ -2728 +2728 @@
 
         ob_start();
 
-        $styles = wp_media_mce_styles();
+        $styles = wpview_media_sandbox_styles();
         foreach ( $styles as $style ) {
                 printf( '<link rel="stylesheet" href="%s"/>', $style );
         }

src/wp-includes/media.php

@@ -3308 +3308 @@
  *
  * @return array The relevant CSS file URLs.
  */
-function wp_media_mce_styles() {
+function wpview_media_sandbox_styles() {
         $version = 'ver=' . $GLOBALS['wp_version'];
         $dashicons = includes_url( "css/dashicons.css?$version" );
         $mediaelement = includes_url( "js/mediaelement/mediaelementplayer.min.css?$version" );
         $wpmediaelement = includes_url( "js/mediaelement/wp-mediaelement.css?$version" );
 
-        return array( $dashicons, $mediaelement, $wpmediaelement );
+        /**
+         * For use by themes that need to override the styling of MediaElement previews in the Visual editor.
+         * Not intended for adding editor-style.css. Ideally these styles will be applied by using
+         * the 'seamless' iframe attribute in the future.
+         *
+         * @since 4.0
+         *
+         * @param array The URLs to the stylesheets that will be loaded in the sandbox iframe.
+         */                                     
+        return apply_filters( 'wpview_media_sandbox_styles', array( $dashicons, $mediaelement, $wpmediaelement ) );
 }