diff --git a/dom/base/DOMQuad.h b/dom/base/DOMQuad.h
index 9508d9f431..e32aea26f8 100644
--- a/dom/base/DOMQuad.h
+++ b/dom/base/DOMQuad.h
@@ -24,6 +24,7 @@ class DOMPoint;
 struct DOMQuadJSON;
 struct DOMPointInit;
 struct DOMQuadInit;
+struct DOMRectInit;
 
 class DOMQuad final : public nsWrapperCache
 {