attributeChangedCallback(attr, oldVal, newVal) {
    var component = this.components[attr];
    super.attributeChangedCallback();
    // If the empty string is passed by the component initialization
    // logic we ignore the component update.
    if (component && component.justInitialized && newVal === '') {
      delete component.justInitialized;
      return;
    }
    // When a component is removed after calling el.removeAttribute('material')
    if (!component && newVal === null) {
      return;
    }
    this.setEntityAttribute(attr, oldVal, newVal);
  }
Handle changes coming from the browser DOM inspector.