Swap frame loaders with the given nsIFrameLoaderOwner. This may
only be posible in a very limited range of circumstances, or
never, depending on the object implementing this interface.
@throws NS_ERROR_NOT_IMPLEMENTED if the swapping logic is not
implemented for the two given frame loader owners.
@throws NS_ERROR_DOM_SECURITY_ERR if the swap is not allowed on
security grounds.
The frame loader owned by this nsIFrameLoaderOwner