diff --git a/dom/base/Console.cpp b/dom/base/Console.cpp
index f568ea6519b..8a85984413e 100644
--- a/dom/base/Console.cpp
+++ b/dom/base/Console.cpp
@@ -308,7 +308,7 @@ public:
   }
 
 private:
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() override
   {
     AssertIsOnMainThread();