Version: 52.0.2724.0 76d17b826d6473ef7a4bb731aa8b8dc05aaa5ab6-refs/heads/master@{#391399} (32/64-bit)
OS: Windows (7,8,8.1,10),Linux (14.04 LTS)
URL : chrome://net-internals/#httpCache

What steps will reproduce the problem?
1) Launch chrome and navigate to above URL.
2) Now zoom out the page to 25% and click on down arrow icon to open drop down list located on top RHS of page
3) Scroll bar is displayed on drop down list,now click on up/down arrow icon of scroll bar,observe the down arrow icon of scroll bar

Actual : Down arrow icon of scroll bar is seen disabled even if the list is scrolled up completely.
Expected : Down arrow icon of scroll bar should be seen enabled when the list is scrolled up completely.

This is a regression issue broken in 'M-49' and below is the manual regression and Narrow bisect info:
Good build : 49.0.2578.0
Bad build : 49.0.2579.0

Narrow bisect info:
https://chromium.googlesource.com/chromium/src/+log/565ca59298cf6feaaaba3ece0ce1589bc9f118c9..b867702268009cc8d2be5c67559a1f10e55ee45d?pretty=fuller&n=50

Suspecting : r362357 from Narrow bisect

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

Note : Issue is not seen on Mac OS.
 

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