diff --git a/browser/base/content/content.js b/browser/base/content/content.js
index 7a0a14a9222..17cae71de42 100644
--- a/browser/base/content/content.js
+++ b/browser/base/content/content.js
@@ -36,6 +36,8 @@
 #
 # ***** END LICENSE BLOCK *****
 
+const Ci = Components.interfaces;
+
 const webNavigation = docShell.QueryInterface(Ci.nsIWebNavigation);
 
 addMessageListener("WebNavigation:LoadURI", function(message) {