void JSCanvasRenderingContext2D::setFillStyle(ExecState* exec, JSValue value)
{
    CanvasRenderingContext2D* context = static_cast<CanvasRenderingContext2D*>(impl());
    if (value.isString()) {
        context->setFillColor(asString(value)->value(exec));
        return;
    }
    context->setFillStyle(toHTMLCanvasStyle(exec, value));
}
void JSCanvasRenderingContext2D::setFillStyle(ExecState* exec, JSValue* value)
{
    impl()->setFillStyle(toHTMLCanvasStyle(exec, value));
}