Chrome version :51.0.2662.0 4d223c72fe4e76c7404bffb662f742b947f97107-refs/heads/master@{#378134} (32/64 bit)
OS : Windows(Win 7 aero enabled),Linux.

Steps : 
1. Launch Chrome,navigate to NTP and open devtools 
2. Now go to 'Timeline' section and press 'F5' key from keyboard to record and some data is displayed
3. Now click on 'Bottom-Up' button present on tab strip and resize the window till scroll bar is displayed.
4. Try to continuous scroll up and down using mouse scroll wheel and observe

Actual : Scroll bar doesn't work smoothly.
Expected : Scroll bar should work smoothly.
 
This is a regression issue broken in 'M-49' and below is the manual regression and narrow bisect info.
Good build : 49.0.2614.4
Bad build : 49.0.2615.0

Narrow Bisect :
https://chromium.googlesource.com/chromium/src/+log/ff24f24c28067cd1996f04b36318a9cbb70cbee4..079aeefe2cdbb60ff4e53ce126d229aa850aaffa?pretty=fuller&n=100

Suspecting r367942 from narrow bisect

@skobes : Could you please help to reassign if your change is not the cause for this issue

Note : Issue is not seen on Mac OS.
 

Deleted: Actual_video.mp4 1003 KB

Actual_video.mp4 1003 KB Download

Deleted: Expected_video.mp4 744 KB

Expected_video.mp4 744 KB Download