text: import React, { Component } from 'react';
  import { 
    AppRegistry,
    StyleSheet,
    Text,
    View,
  } from 'react-native';
  import { WebView } from 'react-native-webview';
  export default class MessengerScreen extends Component {
    render() {
      return (
        <WebView
          source={{uri: 'https://www.facebook.com'}}
          style={{marginTop: 20}}
        />
      );
    }
  }
    MessengerScreen.navigationOptions = {
    title: 'Facebook',
  };
  
  // const styles = StyleSheet.create({
  //   container: {
  //     flex: 1,
  //     paddingTop: 15,
  //     backgroundColor: '#fff',
  //   },
  // });