Chrome version :50.0.2661.11 d99fa8d200178bce07b02a15d79512e7236088ee-refs/branch-heads/2661@{#51} (32/64 bit)
OS : Windows(Win 7 aero enabled),Linux.

Steps : 
1. Launch Chrome and open chrome://tracing.
2. Now click on 'Record' button on top LHS of page and record some readings(Some data will be displayed).
3. Now try to drag the 'horizontal drag handle' up so as scroll bar is displayed and try to scroll the window continuously with mouse wheel scroll,observe.

Actual : Vertical scrolling action is not smooth.
Expected : Vertical scrolling action should be smooth. 

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=50

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.
 

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Actual_video.mp4 882 KB Download

Deleted: Expected_video.mp4 872 KB

Expected_video.mp4 872 KB Download