diff --git a/layout/style/nsStyleStruct.h b/layout/style/nsStyleStruct.h
index 9db1b385ac12e0142921c49e6b6c2ba0fadccf95..919089fd9bc278b0c2fede4b2babe133acd4632e 100644
--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -2075,6 +2075,7 @@ 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