operator == method
Compares rectangles for equality. @param {goog.math.Rect} a A Rectangle. @param {goog.math.Rect} b A Rectangle. @return {bool} True iff the rectangles have the same left, top, width, and height, or if both are null.
Implementation
@override
bool operator ==(Object other)
{
  if (other is Rect) {
    return this.left == other.left && this.width == other.width && this.top == other.top && this.height == other.height;
  }
  else {
    return false;
  }
}