message: Use inline class field for PropTypes
diff: @@ -49,6 +49,14 @@ const PE_Z_INDEX = 5000;
  * bounding rect as the parent of PE.
  */
  export default class PersistedElement extends React.Component {
  +
  + static propTypes = {
  + // Unique identifier for this PersistedElement instance
  + // Any PersistedElements with the same persistKey will use
  + // the same DOM container.
  + persistKey: PropTypes.string.isRequired,
  + };
  +
  constructor() {
  super();
  this.collectChildContainer = this.collectChildContainer.bind(this);
  @@ -110,10 +118,3 @@ export default class PersistedElement extends React.Component {
  return <div ref={this.collectChildContainer}></div>;
  }
  }
  -
  -PersistedElement.propTypes = {
  - // Unique identifier for this PersistedElement instance
  - // Any PersistedElements with the same persistKey will use
  - // the same DOM container.
  - persistKey: PropTypes.string.isRequired,
  -};
  