Able to reproduce the issue on Peppy using chrome version 53.0.2746.0/8369.0.0

Issue is also seen in 52.0.2743.0/8350.3.0 (Official Build) dev-channel peppy.

NOTE: Issue is still seen [i.e: Flickering is still seen on hovering on atatch a photo icon or hovering on any of the chat conversations] in 53.0.2754.0/8405.0.0 (Official Build) dev-channel parrot,peach-pit,Jerry

Reproduces for me on a Pixel 2 Dev channel 52.0.2743.19 but not Beta channel.

This may be expected behavior when laying out a 19px and a 17px and trying to balance them using flex box.

cbiesinger@:  can you confirm or deny this?

Pixel 1 on dev does not seem to reproduce the flicker, just the shifting.

The hover state appears to toggle constantly when hovering the element.
Maybe this is an input issue. Perhaps hit testing?

Adding releaseblock-stable since it's a regression, and assigning to a TL for
triage/fix.

Probably building on linux with chromeos=1 will reproduce the problem.

I can reproduce the shifting on a regular windows build with installing the app, no need for chromeos=1 (possibly requires hidpi display??)

Can someone get a bisect?

Oh... the shifting, per se, is because of the flex: 1 -- we compute the width of the flexbox basically by adding up the widths of the children (=18 + 20 + margins). But because the flex: 1 implies flex-basis: 0% (computes to zero here), we lay them out to the same width each, growing/repositioning the button in the process. hangouts should really use flex:none for these. I'm not sure why this would have changed, but we may have considered the 0% to be indefinite and changed it to auto. I can't immediately see why we would have done that, but we did simplify our code in that respect.

This doesn't explain the flickering issue, I don't really know how to debug that one :(

Shifting button is being fixed in the app now.

Maybe this will fix the flickering, too?

Note that this is using a simple CSS :hover rule (using :hover>button { display:block } to show the buttons). I don't know how anything flexbox-specific would cause this.

The shifting is now fixed on the hangouts side; can someone test if that maybe also fixed the flickering? Thanks!

Checked the issue on 53.0.2764.0/8451.0.0 (Official Build) dev-channel daisy and is working fine.

No such shifting or flickering is seen on hovering as mentioned in Comment#0 and #3

Thank you! Closing this bug. No merge needed as the fix was on the hangouts side.