message: adjust prop in HeaderButton
diff: @@ -54,9 +54,8 @@ export default class HeaderButton extends React.Component {
  HeaderButton.propTypes = {
  // Whether this button is highlighted
  isHighlighted: PropTypes.bool.isRequired,
  - // The phase to swap to when the button is clicked
  - clickPhase: PropTypes.string.isRequired,
  -
  + // click handler
  + onClick: PropTypes.func.isRequired,
  // The badge to display above the icon
  badge: PropTypes.node,
  // The parameters to track the click event
  