Chrome Version:67.0.3376.0/10505.0.0 dev channel Daisy,Candy,Reks
OS:Chrome OS

What steps will reproduce the problem?
(1)Sign into user ->go to chrome://settings/manageAccessibility ->In text-to Speech,enable Select-to-speak 
(2)Open Select-to-speak settings page(i.e.,chrome-extension://klbcgckkldhdhonijdbnhhaiedfkllef/options.html)
(3)Press tab and observe the focus on the slider of Select a speech rate

Actual: No focus highlight is seen on the slider of Select a speech rate
Expected: Instead, focus should be seen on the slider of Select a speech rate

Raising it as a Non-Regression issue seen from M-67 as the slider feature is newly introduced.

Note: Issue is not seen in Linux,Windows OS

Attached the screenshots for reference..