Chrome Version: ToT
OS: Chrome

What steps will reproduce the problem?
(1) Open a11y page of MD settings
(2) Enable spoken feedback.

What is the expected result?
Talkback options button should be there next to ChromeVox options button.

What happens instead?
No TalkBack options button.

Additional information
We've added TalkBack options button at  https://crbug.com/635383 
But it seems that we haven't added the button in MD settings.