anchor.diff:    void newline() {
       _append(new BRElement());
     }
  +
  +  void clear() {
  +    var consoleTextElement = $['consoleText'];
  +    consoleTextElement.children.clear();
  +  }
   }
   
   @CustomTag('debugger-input')
  
positive.code:       return new Future.value(null);
      }
      try {
        debugger.currentFrame -= count;
        debugger.console.print('frame = ${debugger.currentFrame}');
      } catch (e) {
        debugger.console.print('frame must be in range [${e.start},${e.end-1}]');
  
negative.code:     return new Future.value(null);
    }
  
    String helpShort = 'Move down one or more frames (hotkey: [Page Down])';
  
    String helpLong =
        'Move down one or more frames.\n'
        '\n'
        'Hotkey: [Page Down]\n'
        '\n'
        'Syntax: down\n'
        '        down <count>\n';
  