--- a/toolkit/components/places/History.cpp
+++ b/toolkit/components/places/History.cpp
@@ -621,34 +621,34 @@ NS_IMPL_ISUPPORTS_INHERITED(
 )
 
 /**
  * Notifies observers about a visit or an array of visits.
  */
 class NotifyManyVisitsObservers : public Runnable
 {
 public:
-  explicit NotifyManyVisitsObservers(VisitData aPlace)
+  explicit NotifyManyVisitsObservers(const VisitData& aPlace)
     : Runnable("places::NotifyManyVisitsObservers")
     , mPlace(aPlace)
     , mHistory(History::GetService())
   {
   }
 
   explicit NotifyManyVisitsObservers(nsTArray<VisitData>& aPlaces)
     : Runnable("places::NotifyManyVisitsObservers")
     , mHistory(History::GetService())
   {
     aPlaces.SwapElements(mPlaces);
   }
 
   nsresult NotifyVisit(nsNavHistory* aNavHistory,
                        nsCOMPtr<nsIObserverService>& aObsService,
                        PRTime aNow,
-                       VisitData aPlace) {
+                       const VisitData& aPlace) {
     nsCOMPtr<nsIURI> uri;
     MOZ_ALWAYS_SUCCEEDS(NS_NewURI(getter_AddRefs(uri), aPlace.spec));
     if (!uri) {
       return NS_ERROR_UNEXPECTED;
     }
     // Notify the visit.  Note that TRANSITION_EMBED visits are never added
     // to the database, thus cannot be queried and we don't notify them.
     if (aPlace.transitionType != nsINavHistoryService::TRANSITION_EMBED) {