code/Debug/Model/Observer.php
public function onActionPreDispatch(Varien_Event_Observer $observer)
    {
        if (!$this->canCollect()) {
            return;
        }

        $action = $observer->getData('controller_action');

        // Record action that handled current request
        $this->getRequestInfo()->initController($action);
    }
public function onActionPreDispatch(Varien_Event_Observer $observer)
    {
        if (!$this->canCollect()) {
            return;
        }

        $action = $observer->getData('controller_action');

        // Record action that handled current request
        $this->getRequestInfo()->initController($action);
    }
Listens to controller_action_predispatch event to capture request information

@param Varien_Event_Observer $observer
@return void