/**
  * Emulate 'viewed products' block with persistent data
  *
  * @param Mage_Reports_Block_Product_Viewed $block
  * @return null
  */
 public function emulateViewedProductsBlock(Mage_Reports_Block_Product_Viewed $block)
 {
     if (!Mage::helper('enterprise_persistent')->isViewedProductsPersist()) {
         return;
     }
     $customerId = $this->_getCustomerId();
     $block->getModel()->setCustomerId($customerId)->calculate();
     $block->setCustomerId($customerId);
 }