FocusMonitor does not remove event handler registered on document and window

[yueluog]

Bug, feature request, or proposal:

In _registerDocumentEvents function, a few event listeners are registered on document and window objects: https://github.com/angular/material2/blob/4d97271786855598cfd18921641d5ffaafa079d8/src/cdk/a11y/focus-monitor.ts#L145
But I cannot find the corresponding removeEventListener. This may cause memory leak.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}