Chrome Version       : 68.0.3437.0
OS Version: 10709.0.0

What steps will reproduce the problem?
1. Log in to a Chromebook with a touch screen 
2. Navigate to any site
3. Tap on the star in the omnibox
4. Tap on the More button

What is the expected result?

The bookmark folder selection is easy by tapping

What happens instead of that?

The bookmark folder selection is not easy by tapping.
I think it'd be easier if the folder icons are a bit larger.


Please provide any additional information below. Attach a screenshot if
possible.

--secondary-ui-md makes the buttons larger, so which is good, but the folder tree is still difficult to navigate by tapping.