diff -r 000000000000 -r 6474c204b198 layout/style/test/browser_bug453896.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/style/test/browser_bug453896.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,27 @@
+var listener = {
+  handleEvent : function(e) {
+    if (e.target == theBrowser.contentDocument)
+      doTest();
+  }
+}
+
+var theTab;
+var theBrowser;
+
+function test() {
+  waitForExplicitFinish();
+
+  theTab = gBrowser.addTab();
+  theBrowser = gBrowser.getBrowserForTab(theTab);
+  theBrowser.addEventListener("load", listener, true);
+  
+  var rootDir = getRootDirectory(gTestPath);
+  theBrowser.contentWindow.location = rootDir + "bug453896_iframe.html";
+}
+
+function doTest() {
+  theBrowser.removeEventListener("load", listener, true);
+  var fake_window = { ok: ok, SimpleTest: { finish: finish } };
+  theBrowser.contentWindow.wrappedJSObject.run(fake_window);
+  gBrowser.removeTab(theTab);
+}