shadow-dom-first-child.html | Explore in Territory

<!doctype html>
<my-custom-element style="display:none"></my-custom-element>
<script>
  class MyCustomElement extends HTMLElement {
    constructor() {
      super();
      this.attachShadow({ mode: 'open' });
     setTimeout(() => {
        var div = document.createElement('div');
        div.innerText = "test"
        this.shadowRoot.appendChild(div);
        div.setAttribute("aria-label", "aria label");
     }, 0);
    }
  }
  customElements.define('my-custom-element', MyCustomElement);
</script>

chromium/content/test/data/accessibility/html/shadow-dom-first-child.html