Dialog: Update classes option to use empty string instead of null

Author: arschmitz

tests/unit/dialog/dialog_common.js

@@ -5,16 +5,16 @@ TestHelpers.commonWidgetTests( "dialog", {
 		buttons: [],
 		classes: {
 			"ui-dialog": "ui-corner-all",
-			"ui-dialog-content": null,
+			"ui-dialog-content": "",
 			"ui-dialog-titlebar": "ui-corner-all",
-			"ui-dialog-titlebar-close": null,
-			"ui-dialog-title": null,
-			"ui-dialog-buttons": null,
-			"ui-dialog-buttonpane": null,
-			"ui-dialog-buttonset": null,
-			"ui-dialog-dragging": null,
-			"ui-dialog-resizing": null,
-			"ui-widget-overlay": null
+			"ui-dialog-titlebar-close": "",
+			"ui-dialog-title": "",
+			"ui-dialog-buttons": "",
+			"ui-dialog-buttonpane": "",
+			"ui-dialog-buttonset": "",
+			"ui-dialog-dragging": "",
+			"ui-dialog-resizing": "",
+			"ui-widget-overlay": ""
 		},
 		closeOnEscape: true,
 		closeText: "Close",

tests/unit/dialog/dialog_common_deprecated.js

@@ -5,16 +5,16 @@ TestHelpers.commonWidgetTests( "dialog", {
 		buttons: [],
 		classes: {
 			"ui-dialog": "ui-corner-all",
-			"ui-dialog-content": null,
+			"ui-dialog-content": "",
 			"ui-dialog-titlebar": "ui-corner-all",
-			"ui-dialog-titlebar-close": null,
-			"ui-dialog-title": null,
-			"ui-dialog-buttons": null,
-			"ui-dialog-buttonpane": null,
-			"ui-dialog-buttonset": null,
-			"ui-dialog-dragging": null,
-			"ui-dialog-resizing": null,
-			"ui-widget-overlay": null
+			"ui-dialog-titlebar-close": "",
+			"ui-dialog-title": "",
+			"ui-dialog-buttons": "",
+			"ui-dialog-buttonpane": "",
+			"ui-dialog-buttonset": "",
+			"ui-dialog-dragging": "",
+			"ui-dialog-resizing": "",
+			"ui-widget-overlay": ""
 		},
 		closeOnEscape: true,
 		closeText: "close",

ui/dialog.js

@@ -37,16 +37,16 @@ $.widget( "ui.dialog", {
 		buttons: [],
 		classes: {
 			"ui-dialog": "ui-corner-all",
-			"ui-dialog-content": null,
+			"ui-dialog-content": "",
 			"ui-dialog-titlebar": "ui-corner-all",
-			"ui-dialog-titlebar-close": null,
-			"ui-dialog-title": null,
-			"ui-dialog-buttons": null,
-			"ui-dialog-buttonpane": null,
-			"ui-dialog-buttonset": null,
-			"ui-dialog-dragging": null,
-			"ui-dialog-resizing": null,
-			"ui-widget-overlay": null
+			"ui-dialog-titlebar-close": "",
+			"ui-dialog-title": "",
+			"ui-dialog-buttons": "",
+			"ui-dialog-buttonpane": "",
+			"ui-dialog-buttonset": "",
+			"ui-dialog-dragging": "",
+			"ui-dialog-resizing": "",
+			"ui-widget-overlay": ""
 		},
 		closeOnEscape: true,
 		closeText: "Close",