This signal is emitted when back_forward_list changes.
This happens when the current item is updated, a new item is added or one or more items are removed. Note that both item_added
and items_removed can null when only the current item is updated. Items are only
removed when the list is cleared or the maximum items limit is reached.
| item_added |
the BackForwardListItem added or null |
| items_removed |
a List of BackForwardListItem<!-- -->s |