LayoutTests/pageoverlay/overlay-remove-reinsert-view.html

<html>
<style>
body {
    height: 5000px;
    width: 5000px;
}
</style>
<script>
    if (window.testRunner) {
        testRunner.dumpAsText();
        testRunner.waitUntilDone();
    }

    function getWaitForPresentationUpdateUIScript()
    {
        return `
        (function() {
            uiController.doAfterPresentationUpdate(function() {
                uiController.uiScriptComplete('');
            });
        })();`
    }

    function getUnparentUIScript()
    {
        return `
        (function() {
            uiController.removeViewFromWindow(function() {
                uiController.uiScriptComplete('');
            });
        })();`
    }

    function getReinsertUIScript()
    {
        return `
        (function() {
            uiController.addViewToWindow(function() {
                uiController.uiScriptComplete('');
            });
        })();`
    }

    function dumpLayers(outputId)
    {
        if (window.internals) {
            document.getElementById(outputId).innerText = window.internals.pageOverlayLayerTreeAsText(internals.LAYER_TREE_INCLUDES_TILE_CACHES);
        }
    }

    function doTest()
    {
        if (!window.testRunner || !testRunner.runUIScript)
            return;

        internals.installMockPageOverlay("document");
        internals.installMockPageOverlay("view");

        // Waiting for a presentation update is needed to get the document overlay to become tiled.
        testRunner.runUIScript(getWaitForPresentationUpdateUIScript(), function(result) {
            dumpLayers('before-layers');

            testRunner.runUIScript(getUnparentUIScript(), function(result) {
                dumpLayers('view-removed-layers');

                testRunner.runUIScript(getReinsertUIScript(), function(result) {
                    dumpLayers('view-reinsertion-layers');
                    if (window.testRunner)
                        testRunner.notifyDone();
                });
            });
        });
    }

    window.addEventListener('load', doTest, false);
</script>
<body>
    <h2>Initial layers</h2>
    <pre id="before-layers">Layer tree goes here</pre>

    <h2>Layers after removal</h2>
    <pre id="view-removed-layers">Layer tree goes here</pre>

    <h2>Layers after re-insertion</h2>
    <pre id="view-reinsertion-layers">Layer tree goes here</pre>
</body>
</html>