1 files changed, 3 insertions, 0 deletions
diff --git a/layout/style/StyleSheet.h b/layout/style/StyleSheet.h
index f21a6d648..863f6d22f 100644
--- a/layout/style/StyleSheet.h
+++ b/layout/style/StyleSheet.h
@@ -143,6 +143,9 @@ public:
   void DeleteRule(uint32_t aIndex,
                   nsIPrincipal& aSubjectPrincipal,
                   ErrorResult& aRv);
+  int32_t AddRule(const nsAString& aSelector, const nsAString& aBlock,
+                  const dom::Optional<uint32_t>& aIndex,
+                  nsIPrincipal& aSubjectPrincipal, ErrorResult& aRv);
 
   // WebIDL miscellaneous bits
   inline dom::ParentObject GetParentObject() const;