Make CSSSupportsRule function arguments non-optional

Source/core/css/CSSSupportsRule.idl

Index: Source/core/css/CSSSupportsRule.idl
diff --git a/Source/core/css/CSSSupportsRule.idl b/Source/core/css/CSSSupportsRule.idl
index b2aa0cc8dee42282de769a89b5df758c14ba0790..43a81d7bba0c149d9952eafb903dca7f27214929 100644
--- a/Source/core/css/CSSSupportsRule.idl
+++ b/Source/core/css/CSSSupportsRule.idl
@@ -32,7 +32,6 @@
     readonly attribute CSSRuleList cssRules;
     readonly attribute DOMString conditionText;
 
-    [RaisesException] unsigned long insertRule([Default=Undefined] optional DOMString rule,
-                             [Default=Undefined] optional unsigned long index);
-    [RaisesException] void deleteRule([Default=Undefined] optional unsigned long index);
+    [RaisesException] unsigned long insertRule(DOMString rule, unsigned long index);
+    [RaisesException] void deleteRule(unsigned long index);
 };