bisected to https://crrev.com/c/1014568

sadrul@, this will make tablet device (Dru) unusable, so please look into it asap.
let me know if you just want to revert it for now.

https://chromium-review.googlesource.com/c/chromium/src/+/1020085 is the fix I currently have. Briefly, the problem is that SetBoundsInPixels() on WindowTreeHost is called without the size actually changing, or without assigning a valid LocalSurfaceId. It may make sense to move that change so that it takes care of similar issues in other places.

I tested the patch on EVE and it works. The animation smoothness value is consistent with the UMA metrics.

Bumping to p0  because this is causing various graphics glitches on the device. If you can't fix this soon, I'll revert it for now.

Bumping to p0  because this is causing various graphics glitches on the device. If you can't fix this soon, I'll revert it for now.

I will disable some of the tests in mash-browser-tests so the fix in https://chromium-review.googlesource.com/c/chromium/src/+/1020085 can land.

Since mus is no longer turned on by default, this is no longer an issue, right?

If this is not used by default, you can lower to P2.