diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-includes/customize/class-wp-customize-background-image-control.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/customize/class-wp-customize-background-image-control.php	Mon Oct 14 17:39:30 2019 +0200
@@ -0,0 +1,51 @@
+<?php
+/**
+ * Customize API: WP_Customize_Background_Image_Control class
+ *
+ * @package WordPress
+ * @subpackage Customize
+ * @since 4.4.0
+ */
+
+/**
+ * Customize Background Image Control class.
+ *
+ * @since 3.4.0
+ *
+ * @see WP_Customize_Image_Control
+ */
+class WP_Customize_Background_Image_Control extends WP_Customize_Image_Control {
+	public $type = 'background';
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 3.4.0
+	 * @uses WP_Customize_Image_Control::__construct()
+	 *
+	 * @param WP_Customize_Manager $manager Customizer bootstrap instance.
+	 */
+	public function __construct( $manager ) {
+		parent::__construct( $manager, 'background_image', array(
+			'label'    => __( 'Background Image' ),
+			'section'  => 'background_image',
+		) );
+	}
+
+	/**
+	 * Enqueue control related scripts/styles.
+	 *
+	 * @since 4.1.0
+	 */
+	public function enqueue() {
+		parent::enqueue();
+
+		$custom_background = get_theme_support( 'custom-background' );
+		wp_localize_script( 'customize-controls', '_wpCustomizeBackground', array(
+			'defaults' => ! empty( $custom_background[0] ) ? $custom_background[0] : array(),
+			'nonces' => array(
+				'add' => wp_create_nonce( 'background-add' ),
+			),
+		) );
+	}
+}