Unable to reproduce the issue on reported chrome version #69.0.3497.81 and on latest canary #71.0.3543.0 using Mac OS 10.13.6 by following below steps.

Steps:
=====
1.Launched chrome.
2.Navigated to "https://atomiks.github.io/tippyjs/".
3.Scrolled down quickly, observed that the scrolling is done smoothly and unable to observe any flashing on the screen.

Attached screencast for reference.
@reporter: Could you please review the attached screencast and let us know if anything is being missed here. Request you to retry the issue on a new profile without any apps and extensions, reset all flags to default on latest canary and let us know if the issue still persists.
Thanks.!

Deleted: 881165.mp4 2.8 MB

	881165.mp4 2.8 MB View Download

I can repro on Linux. Raster isn't keeping up with the scroll so we're seeing unrastered tiles.

Interestingly, scrolling from the main thread (via scrollbars, for e.g.) is *much* better - even when dragging the scrollbar thumb so we're changing offsets really quickly.

I've attached a trace showing, first, wheel scrolling handled on the compositor and, second, scrollbar scrolling. It seems we're doing a ton or faster in the former case and quite little in the latter. 

Deleted: trace_gradient.json.gz 4.1 MB

trace_gradient.json.gz 4.1 MB Download

I see this on other pages too:  https://wiki.winehq.org/List_Of_Windows_Messages

That doesn't have a gradient but does have background-attachment: fixed. Same deal, main thread scrolling looks great - compositor scrolling shows blank tiles.

Also, when I zoom right in with the trackpad I'm seeing some banding on the gradient itself. Looks like it has been compressed with JPEG. Didn't see that issue in previous versions of Chrome.

Screencast of the white flashing. It also happens in incognito mode with extensions disabled.

Deleted: chrome69-white-flashing.mov 6.6 MB

	chrome69-white-flashing.mov 6.6 MB View Download

I just updated to recent Chrome 69 patch, and it seems to have mostly fixed this. 

When scrolling fast there's some minor white flashing but nowhere near as much as before – about the same amount as Chrome 68. It was never completely free of the flashing though, so maybe there's still some improvement to be made.

I remove the regression here then as it seems to have been fixed in the latest stable. But leave this open for the further improvements.