1. DomName('CanvasRenderingContext2D.arc')
void arc(num x, num y, num radius, num startAngle, num endAngle, [ bool anticlockwise = false ])

Source 

@DomName('CanvasRenderingContext2D.arc')
void arc(num x,  num y,  num radius,  num startAngle, num endAngle,
    [bool anticlockwise = false]) {
  // TODO(terry): This should not be needed: dartbug.com/20939.
  _arc(x, y, radius, startAngle, endAngle, anticlockwise);
}