We've heard a request from folk building a gaming platform on the web that they wish to be able to access the "back/forward" buttons and preventDefault on these.

Specific proposed steps:
- verify what events we fire into the page for these keys on the various desktop platforms (it's implied here that we may fire events in some cases https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/buttons)
- implement a change to fire events in all missing cases
- implement a change so when Keyboard Lock is enabled, these events can also be cancelled