<!doctype html>
<iframe></iframe>
<script>
var t = opener.t;
var iframe = document.getElementsByTagName("iframe")[0];
var history_length;

function load_frame(src) {
   history_length = history.length;
   iframe.src = src;
   var button = document.getElementsByTagName("button")[0];
   button.parentNode.removeChild(button);
}

remove_frame = t.step_func(function() {
  try {
    opener.assert_equals(history.length, history_length + 1, "History length after loading page in iframe");
    iframe.parentNode.removeChild(iframe);
    opener.assert_equals(history.length, history_length, "History length after removing iframe");
    t.done();
  } finally {
    window.close();
  }
});

</script>
<button onclick="load_frame('discard_iframe_history_1-2.html')">Click here</button>