Chrome version : 67.0.3390.0 (Official Build) ae47769a6d274cb8eeca0f8e7b9198d0b043975f-refs/heads/master@{#548636} 32/64 bit
OS : Windows(7,8,8.1,10)

What steps will reproduce the problem?
1. Launch chrome, navigate to chrome://settings and change 'Page zoom' level to 250%.
2. Now middle click on the page and try to autoscroll settings page downwards.
3. Observe.

Actual Result : Autoscrolling does not work on settings page after changing page zoom level to 250%.
Expected Result : Autoscrolling should work on settings page after changing page zoom level to 250%.

This is a regression issue broken in ‘M-61’ and using the per-revision bisect providing the bisect results,
Good build : 61.0.3132.0 (Revision : 479901)
Bad build : 61.0.3133.0 (Revision : 480259)

You are probably looking for a change made after 479930 (known good), but no later than 479931 (first known bad).

CHANGELOG URL: 
https://chromium.googlesource.com/chromium/src/+log/9ede2cde5727eecdb377b57b32c5226d1d41c8ce..5971e47dc08dbb773f58fd6fb13b1df7917fd295

Suspect : https://chromium.googlesource.com/chromium/src/+/5971e47dc08dbb773f58fd6fb13b1df7917fd295

@aelias : Could you please look into the issue, pardon me if it has nothing to do with your changes and if possible please assign it to concern owner.

Note : 
1.Issue is not reproducible on Mac(10.12.6) and Linux(14.04 LTS), since middle click autoscroll feature is not available in these OS.
2.Issue is also seen on M-65 Stable(build #65.0.3325.181),Beta M-66(build # 66.0.3359.81) , Dev  M-67 (build #67.0.3386.1) .
 
Thank you.
 

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