text: 
  import Chain from '../Chain'
  import TextViewerView from '../View/Viewer/Text'
  import Viewer from '../Viewer'
  
  /**
   * Viewer Brick for viewing and editing content as plain text.
   */
  export default class TextViewer extends Viewer {
    /**
     * Brick constructor
     */
    constructor () {
      super()
      this._title = 'Text'
      this._viewPrototype = TextViewerView
    }
  
    /**
     * Performs view of given content.
     * @protected
     * @param {string} content
     * @param {function} done Called when performing view has finished.
     */
    performView (content, done) {
      this.getView().setText(content.getString())
      done()
    }
  
    /**
     * Triggered when the text has been changed inside the view.
     * @protected
     * @param {TextViewerView} view
     * @param {string} text
     */
    viewTextDidChange (view, text) {
      let content = new Chain(text)
      this.contentDidChange(content)
    }
  }
  