Remove TreatNullAs=NullString for CSS*Rule

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

Index: LayoutTests/fast/dom/css-element-attribute-js-null.html
diff --git a/LayoutTests/fast/dom/css-element-attribute-js-null.html b/LayoutTests/fast/dom/css-element-attribute-js-null.html
index e0f1a89c273b1c72f70e7faa79cc1b5501b37025..becc945b0d5a8dd8c85357b58163e14f037a7245 100644
--- a/LayoutTests/fast/dom/css-element-attribute-js-null.html
+++ b/LayoutTests/fast/dom/css-element-attribute-js-null.html
@@ -9,7 +9,12 @@
         @media screen {
             .bar { color: blue; }
         }
-        </style>
+        @keyframes name { }
+        @page { }
+    </style>
+    <!-- @charset must be the first rule per spec, and additionally
+         with no leading whitespace per our parser. -->
+    <style>@charset "UTF-8";</style>
     <script>
         function printOut(msg) {
             var console = document.getElementById("console");
@@ -47,31 +52,52 @@
             if (window.testRunner)
                 testRunner.dumpAsText();
 
-            var rules = document.getElementsByTagName('style')[1].sheet.cssRules;
+            var rules = document.styleSheets[1].cssRules;
 
-            var rule = rules.item(0);            
+            var rule = rules[0];
+            var mediaRule = rules[1];
+            var keyframesRule = rules[2];
+            var pageRule = rules[3];
+            var charsetRule = document.styleSheets[2].cssRules[0];
             var style = rule.style;
             var value = style.getPropertyCSSValue('color');
-            var mediaList = rules.item(1).media;
-
+            var mediaList = mediaRule.media;
 
             var listing = [
                 {
                     type: 'CSSRule',
                     elementToUse: rule,
                     attributes: [
-                         // for now, setting cssText does not doing anything. When it gets implemented, the expectedNull
-                         // should become the empty string. 
+                         // 'null' is not a valid rule, so the setter does nothing.
                         {name: 'cssText', expectedNull: '.foo { color: black; }'}
                     ]
                 },
                 {
+                    type: 'CSSCharsetRule',
+                    elementToUse: charsetRule,
+                    attributes: [
+                        {name: 'encoding', expectedNull: 'null'}
+                    ]
+                },
+                {
+                    type: 'CSSKeyframesRule',
+                    elementToUse: keyframesRule,
+                    attributes: [
+                        {name: 'name', expectedNull: 'null'}
+                    ]
+                },
+                {
+                    type: 'CSSPageRule',
+                    elementToUse: pageRule,
+                    attributes: [
+                        {name: 'selectorText', expectedNull: '@page null'}
+                    ]
+                },
+                {
                     type: 'CSSStyleRule',
                     elementToUse: rule,
                     attributes: [
-                         // for now, setting selectorText does not doing anything. When it gets implemented, the expectedNull
-                         // should become the empty string. 
-                        {name: 'selectorText', expectedNull: '.foo'}
+                        {name: 'selectorText', expectedNull: 'null'}
                     ]
                 },
                 {
@@ -87,7 +113,7 @@
                     elementToUse: value,
                     attributes: [
                         // for now, setting cssText does not doing anything. When it gets implemented, the expectedNull
-                        // should become the empty string. 
+                        // should become the empty string.
                         {name: 'cssText', expectedNull: 'black'}
                     ]
                 },
@@ -98,15 +124,8 @@
                         {name: 'mediaText', expectedNull: ''}
                     ]
                 }
-                // ,{
-                //     type: 'PageRule',
-                //     elementToUse: mediaList,
-                //     attributes: [
-                //         {name: 'cssText', expectedNull: ''}
-                //     ]
-                // }
             ];
-            
+
             for (element in listing) {
                 var type = listing[element].type;
                 var elementToUse = listing[element].elementToUse;