1) Load the attached file in test_shell.exe. You should see a box rotated 20deg.
2) Drag the window off screen and back.
3) If you look carefully, you'll see that the edge is now a tiny bit different (a bit darker?).
If you reload, the edges return to the lighter state.
I suspect this is a problem in skia since I couldn't repro on mac. It's also hard to repro on Chromium because it saves a backing store of the image. It's the extra invalidate that causes the border to change.
Created attachment 84303 [details]
Can you post before/after screenshots of what you are seeing?
Created attachment 84314 [details]
better test case
Created attachment 84315 [details]
Created attachment 84316 [details]
(In reply to comment #3)
> Created an attachment (id=84314) [details]
> better test case
This shows a much more noticeable difference. The original test case only differed by a dozen pixels or so.