--- a/netwerk/test/browser/browser_child_resource.js
+++ b/netwerk/test/browser/browser_child_resource.js
@@ -116,17 +116,17 @@ function remoteResolveURI(uri) {
     manager.addMessageListener("Test:ResolvedURI", listener);
     manager.sendAsyncMessage("Test:ResolveURI", uri);
   });
 }
 
 var loadTestTab = Task.async(function*() {
   gBrowser.selectedTab = gBrowser.addTab(TEST_URL);
   let browser = gBrowser.selectedBrowser;
-  yield waitForEvent(browser, "load", true);
+  yield BrowserTestUtils.browserLoaded(browser);
   browser.messageManager.loadFrameScript("data:,(" + frameScript.toString() + ")();", true);
   return browser;
 });
 
 // Restarts the child process by crashing it then reloading the tab
 var restart = Task.async(function*() {
   let browser = gBrowser.selectedBrowser;
   // If the tab isn't remote this would crash the main process so skip it