PointerEvent spec defines the back/forward button but all browsers currently intercept these buttons to perform page navigation.

Spec discussion: https://github.com/w3c/pointerevents/issues/191

This bug tracks chromium TODOs, the exact behavior to implement would depend on the outcome of the spec discussion.

One suggestion is to make page navigation (cancelable) default action of back/forward button click. See  crbug.com/567771#c16 .