Integrate media with the custom background page. fixes #21818, see #21390.

git-svn-id: https://develop.svn.wordpress.org/trunk@22502 602fd350-edb4-49c9-b593-d223f7449a82

wp-admin/js/custom-background.js

@@ -1,7 +1,7 @@
 (function($) {
-
 	$(document).ready(function() {
-		var bgImage = $("#custom-background-image");
+		var bgImage = $("#custom-background-image"),
+			frame;
 
 		$('#background-color').wpColorPicker({
 			change: function( event, ui ) {
@@ -19,6 +19,45 @@
 		$('input[name="background-repeat"]').change(function() {
 			bgImage.css('background-repeat', $(this).val());
 		});
-	});
 
+		$('#choose-from-library-link').click( function( event ) {
+			var $el = $(this);
+
+			event.preventDefault();
+
+			if ( frame ) {
+				frame.open();
+				return;
+			}
+
+			frame = wp.media({
+				title:     $el.data('choose'),
+				library:   {
+					type: 'image'
+				}
+			});
+
+			frame.toolbar.on( 'activate:select', function() {
+				frame.toolbar.view().add({
+					select: {
+						style: 'primary',
+						text:  $el.data('update'),
+
+						click: function() {
+							var attachment = frame.state().get('selection').first();
+							$.post( ajaxurl, {
+								action: 'set-background-image',
+								attachment_id: attachment.id,
+								size: 'full'
+							}, function() {
+								window.location.reload();
+							});
+						}
+					}
+				});
+			});
+
+			frame.state('library');
+		});
+	});
 })(jQuery);