<!DOCTYPE html>
<html>
<body>
<script src="../../resources/js-test.js"></script>
<script>
description("This test checks that the page visibility event propagation does not crash the browser when frames are added / deleted.");
jsTestIsAsync = true;

let visibilityChangeEventCount = 0;

onload = function() {
    debug("Loaded all frames.");

    frame1 = document.getElementById("topFrame1");
    frame2 = document.getElementById("topFrame2");
    frame3 = document.getElementById("topFrame3");
    frame4 = document.getElementById("topFrame4");
    subFrame1 = frame3.contentDocument.getElementById("subIframe1");
    subFrame2 = frame3.contentDocument.getElementById("subIframe2");

    document.addEventListener("visibilitychange", onMainPageVisibilityChange);
    frame2.contentDocument.addEventListener("visibilitychange", onFrame2VisibilityChange);

    // Change the visibility of the current page to invisible.
    if (window.testRunner)
        testRunner.setPageVisibility("hidden");
}

function onMainPageVisibilityChange()
{
    ++visibilityChangeEventCount;
    debug("Received visibilitychange event");

    // Delete frame 4.
    frame4.remove();

        // Delete subframe 2.
    frame3.contentDocument.body.removeChild(subFrame2);

    // Add a new frame to top level.
    frame5 = document.createElement("iframe");
    document.body.appendChild(frame5);

    // Add a new frame to frame2.
    subFrame3 = frame2.contentDocument.createElement("iframe");
    frame2.contentDocument.body.appendChild(subFrame3);

    if (visibilityChangeEventCount == 2)
        finishJSTest();
}

function onFrame2VisibilityChange()
{
    ++visibilityChangeEventCount;
    debug("Received visibilitychange event");

    // Delete frame 1.
    frame1.remove();

    if (visibilityChangeEventCount == 2)
        finishJSTest();
}

</script>
<iframe id="topFrame1"></iframe>
<iframe id="topFrame2"></iframe>
<iframe id="topFrame3" src="resources/page-visibility-iframe-delete-test-frame.html"></iframe>
<iframe id="topFrame4"></iframe>
</body>
</html>