diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-includes/widgets/class-wp-widget-tag-cloud.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/widgets/class-wp-widget-tag-cloud.php	Mon Oct 14 17:39:30 2019 +0200
@@ -0,0 +1,196 @@
+<?php
+/**
+ * Widget API: WP_Widget_Tag_Cloud class
+ *
+ * @package WordPress
+ * @subpackage Widgets
+ * @since 4.4.0
+ */
+
+/**
+ * Core class used to implement a Tag cloud widget.
+ *
+ * @since 2.8.0
+ *
+ * @see WP_Widget
+ */
+class WP_Widget_Tag_Cloud extends WP_Widget {
+
+	/**
+	 * Sets up a new Tag Cloud widget instance.
+	 *
+	 * @since 2.8.0
+	 */
+	public function __construct() {
+		$widget_ops = array(
+			'description' => __( 'A cloud of your most used tags.' ),
+			'customize_selective_refresh' => true,
+		);
+		parent::__construct( 'tag_cloud', __( 'Tag Cloud' ), $widget_ops );
+	}
+
+	/**
+	 * Outputs the content for the current Tag Cloud widget instance.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param array $args     Display arguments including 'before_title', 'after_title',
+	 *                        'before_widget', and 'after_widget'.
+	 * @param array $instance Settings for the current Tag Cloud widget instance.
+	 */
+	public function widget( $args, $instance ) {
+		$current_taxonomy = $this->_get_current_taxonomy( $instance );
+
+		if ( ! empty( $instance['title'] ) ) {
+			$title = $instance['title'];
+		} else {
+			if ( 'post_tag' === $current_taxonomy ) {
+				$title = __( 'Tags' );
+			} else {
+				$tax = get_taxonomy( $current_taxonomy );
+				$title = $tax->labels->name;
+			}
+		}
+
+		$show_count = ! empty( $instance['count'] );
+
+		/**
+		 * Filters the taxonomy used in the Tag Cloud widget.
+		 *
+		 * @since 2.8.0
+		 * @since 3.0.0 Added taxonomy drop-down.
+		 * @since 4.9.0 Added the `$instance` parameter.
+		 *
+		 * @see wp_tag_cloud()
+		 *
+		 * @param array $args     Args used for the tag cloud widget.
+		 * @param array $instance Array of settings for the current widget.
+		 */
+		$tag_cloud = wp_tag_cloud( apply_filters( 'widget_tag_cloud_args', array(
+			'taxonomy'   => $current_taxonomy,
+			'echo'       => false,
+			'show_count' => $show_count,
+		), $instance ) );
+
+		if ( empty( $tag_cloud ) ) {
+			return;
+		}
+
+		/** This filter is documented in wp-includes/widgets/class-wp-widget-pages.php */
+		$title = apply_filters( 'widget_title', $title, $instance, $this->id_base );
+
+		echo $args['before_widget'];
+		if ( $title ) {
+			echo $args['before_title'] . $title . $args['after_title'];
+		}
+
+		echo '<div class="tagcloud">';
+
+		echo $tag_cloud;
+
+		echo "</div>\n";
+		echo $args['after_widget'];
+	}
+
+	/**
+	 * Handles updating settings for the current Tag Cloud widget instance.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param array $new_instance New settings for this instance as input by the user via
+	 *                            WP_Widget::form().
+	 * @param array $old_instance Old settings for this instance.
+	 * @return array Settings to save or bool false to cancel saving.
+	 */
+	public function update( $new_instance, $old_instance ) {
+		$instance = array();
+		$instance['title'] = sanitize_text_field( $new_instance['title'] );
+		$instance['count'] = ! empty( $new_instance['count'] ) ? 1 : 0;
+		$instance['taxonomy'] = stripslashes($new_instance['taxonomy']);
+		return $instance;
+	}
+
+	/**
+	 * Outputs the Tag Cloud widget settings form.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param array $instance Current settings.
+	 */
+	public function form( $instance ) {
+		$current_taxonomy = $this->_get_current_taxonomy($instance);
+		$title_id = $this->get_field_id( 'title' );
+		$count = isset( $instance['count'] ) ? (bool) $instance['count'] : false;
+		$instance['title'] = ! empty( $instance['title'] ) ? esc_attr( $instance['title'] ) : '';
+
+		echo '<p><label for="' . $title_id .'">' . __( 'Title:' ) . '</label>
+			<input type="text" class="widefat" id="' . $title_id .'" name="' . $this->get_field_name( 'title' ) .'" value="' . $instance['title'] .'" />
+		</p>';
+
+		$taxonomies = get_taxonomies( array( 'show_tagcloud' => true ), 'object' );
+		$id = $this->get_field_id( 'taxonomy' );
+		$name = $this->get_field_name( 'taxonomy' );
+		$input = '<input type="hidden" id="' . $id . '" name="' . $name . '" value="%s" />';
+
+		$count_checkbox = sprintf(
+			'<p><input type="checkbox" class="checkbox" id="%1$s" name="%2$s"%3$s /> <label for="%1$s">%4$s</label></p>',
+			$this->get_field_id( 'count' ),
+			$this->get_field_name( 'count' ),
+			checked( $count, true, false ),
+			__( 'Show tag counts' )
+		);
+
+		switch ( count( $taxonomies ) ) {
+
+		// No tag cloud supporting taxonomies found, display error message
+		case 0:
+			echo '<p>' . __( 'The tag cloud will not be displayed since there are no taxonomies that support the tag cloud widget.' ) . '</p>';
+			printf( $input, '' );
+			break;
+
+		// Just a single tag cloud supporting taxonomy found, no need to display a select.
+		case 1:
+			$keys = array_keys( $taxonomies );
+			$taxonomy = reset( $keys );
+			printf( $input, esc_attr( $taxonomy ) );
+			echo $count_checkbox;
+			break;
+
+		// More than one tag cloud supporting taxonomy found, display a select.
+		default:
+			printf(
+				'<p><label for="%1$s">%2$s</label>' .
+				'<select class="widefat" id="%1$s" name="%3$s">',
+				$id,
+				__( 'Taxonomy:' ),
+				$name
+			);
+
+			foreach ( $taxonomies as $taxonomy => $tax ) {
+				printf(
+					'<option value="%s"%s>%s</option>',
+					esc_attr( $taxonomy ),
+					selected( $taxonomy, $current_taxonomy, false ),
+					$tax->labels->name
+				);
+			}
+
+			echo '</select></p>' . $count_checkbox;
+		}
+	}
+
+	/**
+	 * Retrieves the taxonomy for the current Tag cloud widget instance.
+	 *
+	 * @since 4.4.0
+	 *
+	 * @param array $instance Current settings.
+	 * @return string Name of the current taxonomy if set, otherwise 'post_tag'.
+	 */
+	public function _get_current_taxonomy($instance) {
+		if ( !empty($instance['taxonomy']) && taxonomy_exists($instance['taxonomy']) )
+			return $instance['taxonomy'];
+
+		return 'post_tag';
+	}
+}