anchor.diff:  Window window = new Window();
   
   class ClientRect {
  -    double top
  +    double top;
       double right;
       double bottomr;
       double left;
  
positive.code: }
  
  class HTMLImageElement extends Element {
    Image();
    String src;
    Object style = {};
  }
  
negative.code:     new Timer(const Duration(milliseconds: 16), () {
        _callRAF(fn);
      });
      return 1;
    }
  
    void cancelAnimationFrame(int id) {
  