message: Guard onStatusBarVisible/Hidden with this.unmounted
diff: @@ -1332,12 +1332,14 @@ module.exports = React.createClass({
  },
  onStatusBarVisible: function() {
  + if (this.unmounted) return;
  this.setState({
  statusBarVisible: true,
  });
  },
  onStatusBarHidden: function() {
  + if (this.unmounted) return;
  this.setState({
  statusBarVisible: false,
  });
  