code/Debug/Model/RequestInfo.php
public function addLayout(Mage_Core_Model_Layout $layout, Mage_Core_Model_Design_Package $design)
    {
        $this->getDesign()->init($layout, $design);
    }
public function addLayout(Mage_Core_Model_Layout $layout, Mage_Core_Model_Design_Package $design)
    {
        $this->getDesign()->init($layout, $design);
    }
Captures layout information

@param Mage_Core_Model_Layout $layout
@param Mage_Core_Model_Design_Package $design