src/Cart/ShoppingCartController.php
public function clear($request)
    {
        $this->updateLocale($request);
        $this->cart->clear();
        $this->extend('updateClearResponse', $request, $response);
        return $response ? $response : self::direct();
    }
public function clear($request)
    {
        $this->updateLocale($request);
        $this->cart->clear();
        $this->extend('updateClearResponse', $request, $response);
        return $response ? $response : self::direct();
    }
Action: clear the cart

@param HTTPRequest $request

@return HTTPResponse