<!DOCTYPE html>

<html>
<head>
  <style type="text/css" media="screen">
    iframe {
        border: 10px solid black;
        padding: 5px;
        margin: 20px;
        height: 150px;
        width: 300px;
        -webkit-box-shadow: 0 0 20px black;
    }
    
    .overlay {
      position: absolute;
      width: 50px;
      height: 50px;
      top: 5px;
      left: 5px;
      background-color: rgba(0, 0, 0, 0.2);
    }
    
  </style>
  <script type="text/javascript" charset="utf-8">
    if (window.testRunner) {
        testRunner.dumpAsText();
        testRunner.waitUntilDone();
    }

    function doTest()
    {
        // For some reason this delay is required for AppKit to not short-circuit the display.
        window.setTimeout(function() {
            var hadLayersBefore = false;
            var hadLayersAfter = false;
            if (window.testRunner) {
                testRunner.display(); // Need to paint for overlap testing.
                hadLayersBefore = window.internals.layerTreeAsText(document) != "";
            }

            document.getElementById('parent-iframe').src = "about:blank";
            
            window.setTimeout(function() {
                if (window.testRunner) {
                    hadLayersAfter = window.internals.layerTreeAsText(document) != "";

                    var results = document.getElementById('results');
                    if (hadLayersBefore && !hadLayersAfter)
                        results.innerText = "PASS: layers disappeared when iframe source changed."
                    else if (!hadLayersBefore)
                        results.innerText = "FAIL: should have initially had layers, but did not."
                    else if (hadLayersAfter)
                        results.innerText = "FAIL: layers did not disappear when iframe source changed."

                    testRunner.notifyDone();
                }
            }, 0);
        }, 0);
    }
    
    window.addEventListener('load', doTest, false);
  </script>
</head>
<body>

    <iframe id="parent-iframe" src="resources/composited-subframe.html"></iframe>
    
    <div class="overlay">
    </div>

    <p>The iframe content was removed. There should be no layers here.</p>
    <p id="results">This test needs to be run in DRT.</p>
</body>
</html>