Google Chrome 66.0.3349.0 (Official Build) canary (64-bit) (cohort: 64-Bit) 
Google Chrome 64.0.3282.167 (Official Build) (64-bit) (cohort: Stable)
Note: there has been a change in UI between 64 and 66 but this issue affects both builds. 

Windows 10 Enterprise Version 1607		
NVDA 2017.4

Report from dsexton@:

The tree control lacks a role and thus it is not clear to screen reader users that it is a list or tree. 
It is not clear to screen reader users which level each item is at in the tree. This makes it difficult to understand which level the bookmark will appear in the bookmarks menu