<!DOCTYPE html>
<html>
<style>
    body { margin: 0; }

    #frame {
        width: 200px;
        height: 200px;
        will-change: opacity;
    }
</style>
<body>
<a href="#">This</a> is a link, outside the frame.<br/>
<iframe id="frame" srcdoc="<a href='#'>This</a> is a link, inside the frame."></iframe>

<pre id="results"></pre>
<script>
if (window.testRunner)
    testRunner.dumpAsText();

window.onload = function () {
    if (window.internals)
       results.textContent = internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_EVENT_REGION | internals.LAYER_TREE_INCLUDES_ROOT_LAYER_PROPERTIES);
};
</script>
</body>
</html>