KSES: Support the video element's playsinline attribute.

Allow users without the `unfiltered_html` capability to use the `playsinline` attribute when embedding videos.

Additionally this adds unit tests for passing the video element through kses.

Fixes #50167. See #29826.

Built from https://develop.svn.wordpress.org/trunk@47837


git-svn-id: http://core.svn.wordpress.org/trunk@47613 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/kses.php

@@ -397,15 +397,16 @@ if ( ! CUSTOM_TAGS ) {
 		),
 		'var'        => array(),
 		'video'      => array(
-			'autoplay' => true,
-			'controls' => true,
-			'height'   => true,
-			'loop'     => true,
-			'muted'    => true,
-			'poster'   => true,
-			'preload'  => true,
-			'src'      => true,
-			'width'    => true,
+			'autoplay'    => true,
+			'controls'    => true,
+			'height'      => true,
+			'loop'        => true,
+			'muted'       => true,
+			'playsinline' => true,
+			'poster'      => true,
+			'preload'     => true,
+			'src'         => true,
+			'width'       => true,
 		),
 	);
 

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-alpha-47836';
+$wp_version = '5.5-alpha-47837';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.