Those gif are putting in a div with css display none, and overflow scroll.
When changing this div container to be display: block;. That scroll area will started to be lag.

Could you please provide us with a test case or example URL so we can try to figure out what went wrong and what fixed it?

I found this problems also on the Discord, they provide a user upload GIF as emoji function. Those emoji GIF on the selection box trigger this bug. I would try to create a similar situation for you. 

Thank you for providing more feedback. Adding the requester to the cc list.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

https://sk-knower.com/chrome_test.html

Here is the test url. I found that the setting of ::-webkit-scrollbar-thumb css will be the key of this bug.

Steps to reproduce the problem:
1. scroll those GIF
2. click on the close and open button
3. try to scroll it again and it started lag.

Unable to reproduce the issue on reported chrome version 64.0.3282.186 using Windows 10 with the below mentioned steps.
1. Launched Chrome
2. Navigated to https://sk-knower.com/chrome_test.html
3. Scrolled up and down
4. Clicked on close and open button
5. Tried scrolling again.
We didn't observe any lag while scrolling. Attaching the screen cast of the same.

@Reporter: Could you please have a look at the screen cast and let us know if we have missed anything. Any further inputs from your end may help us.

Deleted: 817744.mp4 3.7 MB

	817744.mp4 3.7 MB View Download

As you show on your video, 
The first scroll on 0:11-0:13 is very smooth.
But 0:28-0:29-0:31, can you see that scroll is jumping from the top to the bottom?

When those step repeat. It will crash.

Thank you for providing more feedback. Adding the requester to the cc list.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

https://youtu.be/YeOzXIg5aRE

Here is my test video.
I tested on incognito tab(with no plugin running), but the bug will also on normal tab.

0:05-0:09 smooth scrolling
0:10 change the display setting
0:11-0:19 keep scrolling started lag
0:20 back to normal smooth scrolling
0:24 try to change the display setting again
0:25-END try to keep changing the display setting and scroll, BUT the page no respond (KEEP CLICKING)

Assigning for another pass at test verification.

The NextAction date has arrived: 2018-03-19

Apparently assignment didn't stick. Need verification if possible, otherwise re-assign.

Unable to retest and confirm the issue as navigating to https://sk-knower.com/chrome_test.html gives us Error 404 Not found. 
Attaching the screen cast of the same. As per comment#13 re-assigning it back.

Thanks!

Deleted: 817744.mp4 3.1 MB

	817744.mp4 3.1 MB View Download

Please provide a new test URL if this is still a problem. Then we can re-open the issue.

Thanks for followup this problems.
The latest version of chrome have fixed this issues.
If you would like to keep reference of the test page. I can provide the source code again.

Thanks for telling us that the issue is fixed. Sorry for not being faster to triage.