Test setting string properties to null on <audio>, <video>, <source> and <track>

LayoutTests/fast/dom/element-attribute-js-null.html

Index: LayoutTests/fast/dom/element-attribute-js-null.html
diff --git a/LayoutTests/fast/dom/element-attribute-js-null.html b/LayoutTests/fast/dom/element-attribute-js-null.html
index 8029811f16ee5af93ae4a4a5e57ca5314dc2eeac..6d75e8bd2305feb53ce8e521ca71d2e37ad48fee 100644
--- a/LayoutTests/fast/dom/element-attribute-js-null.html
+++ b/LayoutTests/fast/dom/element-attribute-js-null.html
@@ -139,6 +139,15 @@
                     ]
                 },
                 {
+                    type: 'HTMLAudioElement',
+                    elementToUse: document.createElement('audio'),
+                    attributes: [
+                        {name: 'mediaGroup', expectedNull: ''},
+                        {name: 'preload', expectedNull: 'auto'},
+                        {name: 'src', expectedNull: ''}
+                    ]
+                },
+                {
                     type: 'HTMLBaseElement',
                     elementToUse: document.createElement('base'),
                     attributes: [
@@ -483,6 +492,15 @@
                     ]
                 },
                 {
+                    type: 'HTMLSourceElement',
+                    elementToUse: document.createElement('source'),
+                    attributes: [
+                        {name: 'media', expectedNull: 'null'},
+                        {name: 'src', expectedNull: ''},
+                        {name: 'type', expectedNull: 'null'}
+                    ]
+                },
+                {
                     type: 'HTMLStyleElement',
                     elementToUse: document.createElement('style'),
                     attributes: [
@@ -579,11 +597,31 @@
                     ]
                 },
                 {
+                    type: 'HTMLTrackElement',
+                    elementToUse: document.createElement('track'),
+                    attributes: [
+                        {name: 'kind', expectedNull: 'subtitles'},
+                        {name: 'label', expectedNull: 'null'},
+                        {name: 'src', expectedNull: ''},
+                        {name: 'srclang', expectedNull: 'null'}
+                    ]
+                },
+                {
                     type: 'HTMLUListElement',
                     elementToUse: document.createElement('ul'),
                     attributes: [
                         {name: 'type', expectedNull: ''}
                     ]
+                },
+                {
+                    type: 'HTMLVideoElement',
+                    elementToUse: document.createElement('video'),
+                    attributes: [
+                        {name: 'mediaGroup', expectedNull: ''},
+                        {name: 'poster', expectedNull: ''},
+                        {name: 'preload', expectedNull: 'auto'},
+                        {name: 'src', expectedNull: ''}
+                    ]
                 }
             ];