diff --git a/dom/base/ElementInlines.h b/dom/base/ElementInlines.h
index df2cc2e24..ad042e063 100644
--- a/dom/base/ElementInlines.h
+++ b/dom/base/ElementInlines.h
@@ -8,6 +8,7 @@
 #define mozilla_dom_ElementInlines_h
 
 #include "mozilla/dom/Element.h"
+#include "nsIContentInlines.h"
 #include "nsIDocument.h"
 
 namespace mozilla {