diff --git a/brightray/browser/mac/cocoa_notification.h b/brightray/browser/mac/cocoa_notification.h
index 07de1c0875..a6411d924f 100644
--- a/brightray/browser/mac/cocoa_notification.h
+++ b/brightray/browser/mac/cocoa_notification.h
@@ -28,7 +28,7 @@ class CocoaNotification : public Notification {
             const SkBitmap& icon,
             bool silent,
             const bool has_reply,
-            const base::string16 reply_placeholder) override;
+            const base::string16& reply_placeholder) override;
   void Dismiss() override;
 
   void NotificationDisplayed();