anchor.diff:    final double borderRadius;
     final double height;
     final EdgeDims padding;
  -  final PerformanceView performance;
  +  final Animated<double> animation;
     final Point target;
     final double verticalOffset;
     final EdgeDims screenEdgeMargin;
  
positive.code:             screenEdgeMargin: screenEdgeMargin,
              preferBelow: preferBelow
            ),
            child: new OldFadeTransition(
              performance: performance,
              opacity: new AnimatedValue<double>(0.0, end: 1.0, curve: Curves.ease),
              child: new Opacity(
                opacity: opacity,
                child: new Container(
  
negative.code:   }
  
    void resetShowTimer() {
      assert(_controller.status == PerformanceStatus.completed);
      assert(_entry != null);
      _timer = new Timer(config.showDuration, hideTooltip);
    }
  