Chrome Version: 52.0.2743.0
Chrome OS Version: 8350.3.0	
Chrome OS Platform: Peppy,(should be occurring on other devices as well)
Network info: Eth0

Vertical scroll bar within the Gaia frame jumps around weirdly when scrolling up/down. (Check video-- https://youtu.be/9Q22fmj47mE) 

Steps To Reproduce:
(1) Easiest way to trigger the scroll bar to be displayed within the Gaia Webview --is to sign in with a brand new user. 
2) Use the scroll bar to scroll up and down

Expected Result:
The scroll bar shall scroll/track smoothly/linearly like butter on a hot pan inclined at 30 degrees.

Actual Result:
The scroll bar jumps around

How frequently does this problem reproduce? (Always, sometimes, hard to
reproduce?)
Always

What is the impact to the user, and is there a workaround? If so, what is
it?
Users that get a new account, sign in for the first time and interact with the  scroll bar when accepting TOS. (as seen in the video). Would be a pretty bad first impression for brand new user sign-ins.