Emircan, sounds like this could be a HW acceleration issue. I took a look at one of the logs and saw errors about too many frames backed up on the receive-side, which sounds like the decoder isn't able to keep up (similar to the other bug we looked at when you were in STO).

holmer@ this is different as it is triggered by a GPU process crash, not slow but completely unresponsive, see below.

The crash is a GPU process as far as the logs show. Unfortunately, we cannot see the stack as we don't seem to have permission for crash upload, see "Ignoring - Non-developer image and no consent given." However, logs indicate that a dump is saved on /sys/class/drm/card0/error. If you can share it, we can file a bug related to it.
In /var/log/messages: 
2017-09-26T12:20:19.462352+13:00 ERR debugd[715]: Failed to call method: org.freedesktop.DBus.Properties.Set: object_path= /f1/w1/wpa_supplicant1: org.freedesktop.DBus.Error.UnknownMethod: Method "Set" with signature "ssv" on interface "org.freedesktop.DBus.Properties" doesn't exist#012
2017-09-26T12:23:29.597793+13:00 INFO kernel: [  221.830952] [drm] stuck on bsd ring
2017-09-26T12:23:29.597823+13:00 INFO kernel: [  221.830968] [drm] GPU crash dump saved to /sys/class/drm/card0/error
2017-09-26T12:23:29.597827+13:00 INFO kernel: [  221.830979] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
2017-09-26T12:23:29.597831+13:00 INFO kernel: [  221.830993] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
2017-09-26T12:23:29.597834+13:00 INFO kernel: [  221.831006] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
2017-09-26T12:23:29.597837+13:00 INFO kernel: [  221.831020] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
2017-09-26T12:23:29.623370+13:00 INFO crash_reporter[3036]: Ignoring - Non-developer image and no consent given.

This triggers us to lose connection to GPU process and we keep recycling buffers with the error below. 
[1:13:0926/122244.739664:WARNING:generic_decoder.cc(75)] Too many frames backed up in the decoder, dropping this one.

We have already addressed this issue on https://chromium-review.googlesource.com/c/chromium/src/+/617808. That CL made it to 63.0.3218.0 and should fall back to SW codec implementations silently. Please let us know if you can still repro the issue after that version.

We have re-tested on Chrome dev channel 63.0.3239.26 release and have noticed that without any warning (screen use to sometimes have green lines starting to appear and the image quality dropped before the crash) the screen now goes blank (black or dark grey).  The video & audio continue to stream from the chromebox, but is unable to display anything on the screen/monitor.

Managed to get some data off the unit as the unit started pausing and going to crash.

Deleted: debug-logs_20171102-124804 1.8 MB

debug-logs_20171102-124804 1.8 MB View Download

It is a similar GPU crash. SW fallback for decode gets triggered differently though.

From /var/log/chrome:
[1:78:1102/124732.225317:WARNING:videodecodersoftwarefallbackwrapper.cc(97)] Decode OK, no longer using the software fallback decoder.
From /var/log/messages:
2017-11-02T12:47:25.536559+13:00 INFO kernel: [  646.041518] [drm] stuck on bsd ring
2017-11-02T12:47:25.536577+13:00 INFO kernel: [  646.041528] [drm] GPU crash dump saved to /sys/class/drm/card0/error
2017-11-02T12:47:25.536579+13:00 INFO kernel: [  646.041536] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
2017-11-02T12:47:25.536582+13:00 INFO kernel: [  646.041546] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
2017-11-02T12:47:25.536584+13:00 INFO kernel: [  646.041558] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
2017-11-02T12:47:25.536586+13:00 INFO kernel: [  646.041570] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
2017-11-02T12:47:25.553929+13:00 INFO crash_reporter[3572]: Consent given - collect udev crash info.

The error is the same as the one reported on https://bugs.chromium.org/p/chromium/issues/detail?id=750554#c11. Merging it with that issue.