diff --git a/layout/html/content/src/nsHTMLGenericContent.h b/layout/html/content/src/nsHTMLGenericContent.h
index d17a0b69e42e..a91b20b7fa8b 100644
--- a/layout/html/content/src/nsHTMLGenericContent.h
+++ b/layout/html/content/src/nsHTMLGenericContent.h
@@ -44,6 +44,13 @@ class nsIStyleContext;
 class nsIStyleRule;
 class nsISupportsArray;
 
+enum nsSetAttrNotify {
+  eSetAttrNotify_None = 0,
+  eSetAttrNotify_Render = 1,
+  eSetAttrNotify_Reflow = 2,
+  eSetAttrNotify_Restart = 3
+};
+
 struct nsHTMLGenericContent {
   nsHTMLGenericContent();
   ~nsHTMLGenericContent();
@@ -142,6 +149,12 @@ struct nsHTMLGenericContent {
 
   //----------------------------------------
 
+  nsresult SetAttr(nsIAtom* aAttribute, const nsString& aValue,
+                   nsSetAttrNotify aNotify);
+
+  nsresult SetAttr(nsIAtom* aAttribute, const nsHTMLValue& aValue,
+                   nsSetAttrNotify aNotify);
+
   nsresult AddScriptEventListener(nsIAtom* aAttribute,
                                   nsHTMLValue& aValue,
                                   REFNSIID aIID);