diff --git a/uriloader/exthandler/tests/unit_ipc/test_encoding.js b/uriloader/exthandler/tests/unit_ipc/test_encoding.js
index 3c4b61d94f15..ea6a98192c5f 100644
--- a/uriloader/exthandler/tests/unit_ipc/test_encoding.js
+++ b/uriloader/exthandler/tests/unit_ipc/test_encoding.js
@@ -108,6 +108,8 @@ function initChildTestEnv()
     const Cc = Components.classes;                                             \
     const Ci = Components.interfaces;                                          \
     const Cr = Components.results;                                             \
+    const Cu = Components.utils;                                               \
+    Cu.import("resource://gre/modules/Services.jsm");                          \
     function WindowContext() { }                                               \
                                                                                \
     WindowContext.prototype = {                                                \