import findNodeHandle from 'findNodeHandle';
import ScrollingScreenshot from 'react-native-scrolling-screenshot';

var ref = findNodeHandle(this.refs.webview);
ScrollingScreenshot.takeScreenshot(ref, (error, result) => {
  if (error) {
    console.log(error);
  } else {
  	// And the result in your PhotoAlbum
    console.log(result)
  }
});