diff --git a/toolkit/components/url-classifier/Classifier.cpp b/toolkit/components/url-classifier/Classifier.cpp
index 5ee75d485e9c..7c610e12b388 100644
--- a/toolkit/components/url-classifier/Classifier.cpp
+++ b/toolkit/components/url-classifier/Classifier.cpp
@@ -22,6 +22,7 @@
 #include "mozilla/Base64.h"
 #include "mozilla/Unused.h"
 #include "mozilla/SizePrintfMacros.h"
+#include "mozilla/UniquePtr.h"
 #include "nsIUrlClassifierUtils.h"
 #include "nsUrlClassifierDBService.h"
 
@@ -62,7 +63,7 @@ public:
 
 private:
   nsTArray<TableUpdate*>* mUpdatesArrayRef;
-  nsTArray<nsAutoPtr<TableUpdate>> mUpdatesPointerHolder;
+  nsTArray<UniquePtr<TableUpdate>> mUpdatesPointerHolder;
 };
 
 } // End of unnamed namespace.