--- a/dom/interfaces/base/domstubs.idl
+++ b/dom/interfaces/base/domstubs.idl
@@ -66,15 +66,14 @@ interface nsIDOMCSSValue;
 interface nsIDOMCSSPrimitiveValue;
 interface nsIDOMCSSRule;
 interface nsIDOMCSSRuleList;
 interface nsIDOMCSSStyleSheet;
 interface nsIDOMCSSStyleDeclaration;
 interface nsIDOMCounter;
 interface nsIDOMRect;
 interface nsIDOMCSSStyleRule;
-interface nsIDOMCSSStyleRuleCollection;
 
 // Range
 interface nsIDOMRange;
 
 // Crypto
 interface nsIDOMCrypto;