--- a/dom/canvas/test/webgl-mochitest/mochi-to-testcase.py
+++ b/dom/canvas/test/webgl-mochitest/mochi-to-testcase.py
@@ -45,16 +45,20 @@ function ok(val, text) {
 }
 
 function todo(val, text) {
   var status = val ? 'Test <font color=\\'orange\\'>UNEXPECTED PASS</font>: '
                    : 'Test <font color=\\'blue\\'  >todo</font>: ';
   debug(status + text);
 }
 
+function addLoadEvent(func) {
+  window.addEventListener('load', func, false);
+}
+
 SimpleTest = {
   waitForExplicitFinish: function() {},
   finish: function() {},
   requestFlakyTimeout: function() {},
 };
 </script>
 <div id='mochi-to-testcase-output'></div>