diff --git a/layout/style/nsStyleStruct.h b/layout/style/nsStyleStruct.h
index 472c15a359ecd7ad0834d479f1acc53b4527f5ac..9f8377ab507b5883b92621160987a97e0be80014 100644
--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -1876,6 +1876,7 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleUIReset {
   // The margin of the window region that should be transparent to events.
   mozilla::StyleLength mMozWindowInputRegionMargin;
   mozilla::StyleTransform mMozWindowTransform;
+  mozilla::StyleTransformOrigin mWindowTransformOrigin;
 
   nsStyleAutoArray<mozilla::StyleTransition> mTransitions;
   // The number of elements in mTransitions that are not from repeating
