diff --git a/content/base/public/Element.h b/content/base/public/Element.h
index e378d373759c..8d474a4aa741 100644
--- a/content/base/public/Element.h
+++ b/content/base/public/Element.h
@@ -265,4 +265,10 @@ inline mozilla::dom::Element* nsINode::AsElement()
   return static_cast<mozilla::dom::Element*>(this);
 }
 
+inline const mozilla::dom::Element* nsINode::AsElement() const
+{
+  MOZ_ASSERT(IsElement());
+  return static_cast<const mozilla::dom::Element*>(this);
+}
+
 #endif // mozilla_dom_Element_h__
diff --git a/content/base/public/nsINode.h b/content/base/public/nsINode.h
index ef833f52de0c..8ae8309c227a 100644
--- a/content/base/public/nsINode.h
+++ b/content/base/public/nsINode.h
@@ -373,6 +373,7 @@ public:
    * for which IsElement() is true.  This is defined inline in Element.h.
    */
   mozilla::dom::Element* AsElement();
+  const mozilla::dom::Element* AsElement() const;
 
   /**
    * Return this node as nsIContent.  Should only be used for nodes for which