Widget: Handle Object.create(null) for options objects

Fixes #15179
Closes gh-1809

Author: scottgonzalez

tests/unit/widget/extend.js

@@ -5,7 +5,7 @@ define( [
 ], function( QUnit, $ ) {
 
 QUnit.test( "$.widget.extend()", function( assert ) {
-	assert.expect( 27 );
+	assert.expect( 28 );
 
 	var ret, empty, optionsWithLength, optionsWithDate, myKlass, customObject, optionsWithCustomObject, nullUndef,
 		target, recursive, obj, input, output,
@@ -108,6 +108,11 @@ QUnit.test( "$.widget.extend()", function( assert ) {
 	assert.deepEqual( input, output, "don't clone arrays" );
 	input.key[ 0 ] = 10;
 	assert.deepEqual( input, output, "don't clone arrays" );
+
+	input = Object.create( null );
+	input.foo = "f";
+	output = $.widget.extend( {}, input );
+	assert.deepEqual( input, output, "Object with no prototype" );
 } );
 
 } );

ui/widget.js

@@ -26,6 +26,7 @@
 }( function( $ ) {
 
 var widgetUuid = 0;
+var widgetHasOwnProperty = Array.prototype.hasOwnProperty;
 var widgetSlice = Array.prototype.slice;
 
 $.cleanData = ( function( orig ) {
@@ -183,7 +184,7 @@ $.widget.extend = function( target ) {
 	for ( ; inputIndex < inputLength; inputIndex++ ) {
 		for ( key in input[ inputIndex ] ) {
 			value = input[ inputIndex ][ key ];
-			if ( input[ inputIndex ].hasOwnProperty( key ) && value !== undefined ) {
+			if ( widgetHasOwnProperty.call( input[ inputIndex ], key ) && value !== undefined ) {
 
 				// Clone objects
 				if ( $.isPlainObject( value ) ) {