anchor.diff:    MediaStream _localStream;
     final _localRenderer = new RTCVideoRenderer();
     bool _inCalling = false;
  +  bool _isTorchOn = false;
     MediaRecorder _mediaRecorder;
     get _isRec => _mediaRecorder != null;
   
  
positive.code:     });
    }
  
    _captureFrame() async {
      String filePath;
      if (Platform.isAndroid) {
  
negative.code:         title: new Text('GetUserMedia API Test'),
          actions: _inCalling
              ? <Widget>[
                  new IconButton(
                    icon: Icon(_isTorchOn ? Icons.flash_off : Icons.flash_on),
                    onPressed: _toggleTorch,
                  ),
                  new IconButton(
                    icon: Icon(Icons.switch_video),
                    onPressed: _toggleCamera,
                  ),
                  new IconButton(
                    icon: Icon(Icons.camera),
                    onPressed: _captureFrame,
  