on() {
    var container = document.createDocumentFragment();
    var test = document.createElement('div');
    container.appendChild(test);
    assert.equal(test.getRootNode(), container, 'getOwnerRoot incorrect when not in root');
    var c1 = createEnabledElement('x-compose');
    var project = c1.$.project;
    project.appendChild(container);
    flush();
    assert.equal(test.getRootNode(), c1.root, 'getOwnerRoot incorrect for child added to element in root');
    project.removeChild(test);
    flush()