diff --git a/content/base/test/test_websocket.html b/content/base/test/test_websocket.html
index 6beb2da225f6..3363342a6d6c 100644
--- a/content/base/test/test_websocket.html
+++ b/content/base/test/test_websocket.html
@@ -129,15 +129,11 @@ function CreateTestWS(ws_location, ws_protocol)
 
 function forcegc()
 {
-  netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
-  Components.utils.forceGC();
-  var wu =  window.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
-                  .getInterface(Components.interfaces.nsIDOMWindowUtils);
-  wu.garbageCollect();
+  SpecialPowers.forceGC();
+  SpecialPowers.gc();
   setTimeout(function()
   {
-    netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
-    wu.garbageCollect();
+    SpecialPowers.gc();
   }, 1);
 }
 
diff --git a/content/base/test/test_ws_basic_tests.html b/content/base/test/test_ws_basic_tests.html
index 1a06efa153b6..a656e47a862d 100644
--- a/content/base/test/test_ws_basic_tests.html
+++ b/content/base/test/test_ws_basic_tests.html
@@ -22,11 +22,8 @@ var params = ["protocol", "resource", "origin", "end"];
 var results = ["test", "/tests/content/base/test/file_ws_basic_tests", "http://mochi.test:8888", "end"];
 
 function forcegc(){
-  netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
-  Components.utils.forceGC();
-  var wu =  window.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
-                  .getInterface(Components.interfaces.nsIDOMWindowUtils);
-  wu.garbageCollect();
+  SpecialPowers.forceGC();
+  SpecialPowers.gc();
 }
 
 function finishWSTest() {
diff --git a/testing/mochitest/specialpowers/content/specialpowers.js b/testing/mochitest/specialpowers/content/specialpowers.js
index 297c8de38aa8..8473628977f9 100644
--- a/testing/mochitest/specialpowers/content/specialpowers.js
+++ b/testing/mochitest/specialpowers/content/specialpowers.js
@@ -212,6 +212,10 @@ SpecialPowers.prototype = {
     this.DOMWindowUtils.garbageCollect();
   },
 
+  forceGC: function() {
+    Components.utils.forceGC();
+  },
+
   hasContentProcesses: function() {
     try {
       var rt = Cc["@mozilla.org/xre/app-info;1"].getService(Ci.nsIXULRuntime);