B2G/gecko/browser/components/tabview/modules/utils.jsm
//  - A <Point> or two arguments: x and y
A  or two arguments: x and y
A or two arguments : x and y
function Rect_offset(a, b) {
    if (Utils.isPoint(a)) {
      this.left += a.x;
      this.top += a.y;
    } else {
      this.left += a;
      this.top += b;
    }
  }
function Rect_offset ( a , b ) { if ( Utils . isPoint ( a ) ) { this . left += a . x ; this . top += a . y ; } else { this . left += a ; this . top += b ; } }
A <Point> or two arguments: x and y
A <Point > or two arguments : x and y