code: function getSvgArc(currentValue, rotation) {
      var /** @type {?} */ startPoint = rotation || 0;
      var /** @type {?} */ radius = 50;
      var /** @type {?} */ pathRadius = 40;
      var /** @type {?} */ startAngle = startPoint * MAX_ANGLE;
      var /** @type {?} */ endAngle = currentValue * MAX_ANGLE;
      var /** @type {?} */ start = polarToCartesian(radius, pathRadius, startAngle);
      var /** @type {?} */ end = polarToCartesian(radius, pathRadius, endAngle + startAngle);
      var /** @type {?} */ arcSweep = endAngle < 0 ? 0 : 1;
      var /** @type {?} */ largeArcFlag;
      if (endAngle < 0) {
          largeArcFlag = endAngle >= -180 ? 0 : 1;
      }
      else {
          largeArcFlag = endAngle <= 180 ? 0 : 1;
      }
      return "M" + start + "A" + pathRadius + "," + pathRadius + " 0 " + largeArcFlag + "," + arcSweep + " " + end;
  }
docs: Determines the path value to define the arc.  Converting percentage values to to polar
  coordinates on the circle, and then to cartesian coordinates in the viewport.
  
  @param {?} currentValue The current percentage value of the progress circle, the percentage of the
  circle to fill.
  @param {?} rotation The starting point of the circle with 0 being the 0 degree point.
  @return {?} A string for an SVG path representing a circle filled from the starting point to the
  percentage value provided.