_checkInterfaceImplementation(){
        if (this._createDrawingElement === $.DrawerBase.prototype._createDrawingElement) {
            throw(new Error("[drawer]._createDrawingElement must be implemented by child class"));
        }
        if (this.draw === $.DrawerBase.prototype.draw) {
            throw(new Error("[drawer].draw must be implemented by child class"));
        }
        if (this.canRotate === $.DrawerBase.prototype.canRotate) {
            throw(new Error("[drawer].canRotate must be implemented by child class"));
        }
        if (this.destroy === $.DrawerBase.prototype.destroy) {
            throw(new Error("[drawer].destroy must be implemented by child class"));
        }
        if (this.setImageSmoothingEnabled === $.DrawerBase.prototype.setImageSmoothingEnabled) {
            throw(new Error("[drawer].setImageSmoothingEnabled must be implemented by child class"));
        }
    }
Ensures that child classes have provided implementations for public API methods
draw, canRotate, destroy, and setImageSmoothinEnabled. Throws an exception if the original
placeholder methods are still in place.
@private