diff --git a/mozilla/docshell/base/nsIDocShell.idl b/mozilla/docshell/base/nsIDocShell.idl
index ae0f3fb2930..7437e4c9d28 100644
--- a/mozilla/docshell/base/nsIDocShell.idl
+++ b/mozilla/docshell/base/nsIDocShell.idl
@@ -23,7 +23,6 @@
 
 #include "nsISupports.idl"
 #include "domstubs.idl"
-#include "nsIPref.idl"
 #include "nsIURIContentListener.idl"
 #include "nsIURI.idl"