--- a/dom/events/ScrollAreaEvent.cpp
+++ b/dom/events/ScrollAreaEvent.cpp
@@ -17,20 +17,23 @@ ScrollAreaEvent::ScrollAreaEvent(EventTa
                                  nsPresContext* aPresContext,
                                  InternalScrollAreaEvent* aEvent)
   : UIEvent(aOwner, aPresContext, aEvent)
   , mClientArea(new DOMRect(nullptr))
 {
   mClientArea->SetLayoutRect(aEvent ? aEvent->mArea : nsRect());
 }
 
+NS_IMPL_CYCLE_COLLECTION_INHERITED(ScrollAreaEvent, UIEvent,
+                                   mClientArea)
+
 NS_IMPL_ADDREF_INHERITED(ScrollAreaEvent, UIEvent)
 NS_IMPL_RELEASE_INHERITED(ScrollAreaEvent, UIEvent)
 
-NS_INTERFACE_MAP_BEGIN(ScrollAreaEvent)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(ScrollAreaEvent)
 NS_INTERFACE_MAP_END_INHERITING(UIEvent)
 
 void
 ScrollAreaEvent::InitScrollAreaEvent(const nsAString& aEventType,
                                      bool aCanBubble,
                                      bool aCancelable,
                                      nsGlobalWindow* aView,
                                      int32_t aDetail,

--- a/dom/events/ScrollAreaEvent.h
+++ b/dom/events/ScrollAreaEvent.h
@@ -19,17 +19,17 @@ namespace dom {
 class ScrollAreaEvent : public UIEvent
 {
 public:
   ScrollAreaEvent(EventTarget* aOwner,
                   nsPresContext* aPresContext,
                   InternalScrollAreaEvent* aEvent);
 
   NS_DECL_ISUPPORTS_INHERITED
-
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ScrollAreaEvent, UIEvent)
   NS_FORWARD_NSIDOMUIEVENT(UIEvent::)
 
   NS_FORWARD_TO_EVENT_NO_SERIALIZATION_NO_DUPLICATION
   NS_IMETHOD DuplicatePrivateData() override
   {
     return Event::DuplicatePrivateData();
   }
   NS_IMETHOD_(void) Serialize(IPC::Message* aMsg, bool aSerializeInterfaceType) override;