Photo attached.

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Does taking screenshots work correctly? (because I believe the same compositor code is involved in both ash0screenshot and gesture-nav screenshot)

Regular screenshots work fine.

The problem goes away if I disable browser-side-navigation (PlzNavigate) in about:flags.

+clamy, I'm not sure what component to tag for PlzNavigate.

+creis, carlosk, looks like clamy is away.

The PSA mentions PlzNavigate performance issues with cached back/forward navigations, I wonder if it could be related, like a race.

https://groups.google.com/a/chromium.org/d/msg/chromium-dev/U0VowGH6ilw/K4Zkrvj5BwAJ

Possibly a duplicate of  issue 767394 ?

Does it repro if you use the regular buttons for doing back/forward navigations?

Re question in description there is  bug 767680  and friends affecting samus and lulu

I'm unable to repro this on 61.0.3163.108 on my samus.

Is PlzNavigate on by default? Or is it only affecting a portion of the population? If it's finch controlled we should disable it on beta and stable until the issue is fixed (and remove the releaseblock label)

PlzNavigate is indeed on 100% for M61 and later, except Android WebView. It looks like this is affecting specific devices on ChromeOS, so I would rather not disable all of PlzNavigate.
Can this be reproduced on a linux build of Chrome for ChromeOS? If yes, then debugging might be easier to allow us to narrow down a root cause.

I cannot reproduce this on the same version, 61.0.3163.108 on link, with the same account. Also, my repro on samus is now flaky -- sometimes it works OK.

Given that I'm the only one who has seen this, and only on one machine, dropping ReleaseBlock label.

It does not repro with the normal back/forward buttons, just gesture nav.

I don't know how to trigger gesture nav on a linux Chrome for Chrome OS build, as it requires two-finger swipes.

mohsen/sadrul, is there a way to simulate gesture nav on desktop?

I'm also unable to repro this on my Minnie. Adding mfomitchev@ who has worked on screenshot gesture nav and might know better what's happening here.

Re #12: You can use touch emulation on desktop and do the gesture nav using touch ('--touch-events=enabled --touch-devices=<id>' where <id> is id of the mouse device you want to use to emulate touch which can be retrieved using 'xinput list' command).

How do you simulate two-finger swipe with touch-emulation?

You can try gesture nav with touchscreen (or touch-emulation). If you specifically want to try gesture nav with touchpad two-finger swipe, I have no idea!

The white background is used when the screenshot is empty or doesn't match the size of the web contents (see https://cs.chromium.org/chromium/src/ui/aura_extra/image_window_delegate.cc?sq=package:chromium&dr=CSs&l=73).

If we see black, this means that the screenshot was "taken", but for some reason it is all black. Considering screenshots work fine otherwise, this sounds like a race condition between the destruction of the renderer and the readback logic. 

Note that we are in the process of replacing the existing gesture nav UI with the "simplified" MD UI that doesn't use screenshots, but that won't happen until M64.

I was able to test this on linux (on a ChromeOS build).
I haven't seen any black screen.

I tested the swipe back/forward navigation with:
./out/Release/chrome --touch-devices=<mouse_id_from_xinput>

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Obsolete as there is no gesture-nav with screenshot anymore.