Widgets: Include `widget_text` class name on Custom HTML widget wrapper for theme styling compatibility, in addition to previously-added `textwidget` class on nested content container.

Amends [40893], [41115].
See #40907.
Fixes #41392 for trunk.

Built from https://develop.svn.wordpress.org/trunk@41116


git-svn-id: http://core.svn.wordpress.org/trunk@40956 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-alpha-41115';
+$wp_version = '4.9-alpha-41116';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.

wp-includes/widgets/class-wp-widget-custom-html.php

@@ -75,6 +75,9 @@ class WP_Widget_Custom_HTML extends WP_Widget {
 		 */
 		$content = apply_filters( 'widget_custom_html_content', $content, $instance, $this );
 
+		// Inject the Text widget's container class name alongside this widget's class name for theme styling compatibility.
+		$args['before_widget'] = preg_replace( '/(?<=\sclass=["\'])/', 'widget_text ', $args['before_widget'] );
+
 		echo $args['before_widget'];
 		if ( ! empty( $title ) ) {
 			echo $args['before_title'] . $title . $args['after_title'];