B2G/gecko/browser/base/content/aboutDialog.js
// true when there is an update download in progress.
true when there is an update download in progress.
true when there is an update download in progress .
get isDownloading() {
    if (this.update)
      return this.update.state == "downloading";
    return this.um.activeUpdate &&
           this.um.activeUpdate.state == "downloading";
  }
get isDownloading ( ) { if ( this . update ) return this . update . state == "downloading" ; return this . um . activeUpdate && this . um . activeUpdate . state == "downloading" ; }
true when there is an update download in progress.
true when there is an update download in progress .