This class constructor can be extended like any other PHP class constructor, just make sure to pass the same parameters that the extended \Magento\Customer\Block\Account\Dashboard\Info
class is using.
In your case the Info.php
constructor looks something like this:
public function __construct(
\Magento\Framework\View\Element\Template\Context $context,
\Magento\Customer\Helper\Session\CurrentCustomer $currentCustomer,
\Magento\Newsletter\Model\SubscriberFactory $subscriberFactory,
\Magento\Customer\Helper\View $helperView,
array $data = []
) {
$this->currentCustomer = $currentCustomer;
$this->_subscriberFactory = $subscriberFactory;
$this->_helperView = $helperView;
parent::__construct($context, $data);
}
So your class should look something like this:
<?php
namespace Vendor\Customer\Block\Account\Dashboard;
class InfoExtended extends \Magento\Customer\Block\Account\Dashboard\Info
{
public function __construct(
\Magento\Framework\View\Element\Template\Context $context,
\Magento\Customer\Helper\Session\CurrentCustomer $currentCustomer,
\Magento\Newsletter\Model\SubscriberFactory $subscriberFactory,
\Magento\Customer\Helper\View $helperView,
array $data = []
) {
// Your new properties here
parent::__construct($context, $currentCustomer, $subscriberFactory, $helperView, $data);
}
}
BTW, the class you're extending already exposes the current customer session as $currentCustomer
property so you can probably use that without overriding the constructor.