About the packages that were upgraded. This bug appeared a few days before it was reported here on 2017-07-29. I can remember I tried to investigate for a few days before finding and confirming this bug report.

From my file/var/log/apt/history.log.2.gz on my own computer I see that I installed "vdpauinfo" on 2017-07-27, probably in order to investigate this bug:

Start-Date: 2017-07-27  22:30:56
Commandline: apt install vdpauinfo
Requested-By: dimitri (1000)
Install: vdpauinfo:amd64 (1.0-1)
End-Date: 2017-07-27  22:31:01

So the updates responsible for this bug probably occurred hours to days before that. I think this update is responsible:

Start-Date: 2017-07-27  21:32:51
Commandline: aptdaemon role='role-commit-packages' sender=':1.93'
Install: libllvm4.0:amd64 (1:4.0-1ubuntu1~16.04.1, automatic), libllvm4.0:i386 (1:4.0-1ubuntu1~16.04.1, automatic), libwayland-bin:a
md64 (1.12.0-1~ubuntu16.04.1, automatic), libinput-bin:amd64 (1.6.3-1ubuntu1~16.04.1, automatic), libsensors4:i386 (1:3.4.0-2, automatic)
Upgrade: libgles2-mesa:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libdrm-nouveau2:amd64 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libdrm-nouveau2:i386 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libwacom-common:amd64 (0.18-1, 0.22-1~ubuntu16.04.1), libegl1-mesa-dev:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libglapi-mesa:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libglapi-mesa:i386 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), gnome-software:amd64 (3.20.1+git20170524.0.ea2fe2b0-0ubuntu0.16.04.1, 3.20.5-0ubuntu0.16.04.5), xfonts-utils:amd64 (1:7.7+3, 1:7.7+3ubuntu0.16.04.2), libxatracker2:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libwacom-bin:amd64 (0.18-1, 0.22-1~ubuntu16.04.1), libegl1-mesa:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libgbm1:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libwayland-client0:amd64 (1.9.0-1, 1.12.0-1~ubuntu16.04.1), x11proto-core-dev:amd64 (7.0.28-2ubuntu1, 7.0.31-1~ubuntu16.04.1), libdrm-amdgpu1:amd64 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libdrm-amdgpu1:i386 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libwayland-dev:amd64 (1.9.0-1, 1.12.0-1~ubuntu16.04.1), ubuntu-software:amd64 (3.20.1+git20170524.0.ea2fe2b0-0ubuntu0.16.04.1, 3.20.5-0ubuntu0.16.04.5), libwayland-egl1-mesa:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libxfont1:amd64 (1:1.5.1-1, 1:1.5.1-1ubuntu0.16.04.1), libdrm2:amd64 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libdrm2:i386 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libgl1-mesa-dri:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libgl1-mesa-dri:i386 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libgl1-mesa-glx:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libgl1-mesa-glx:i386 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), libdrm-intel1:amd64 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libdrm-intel1:i386 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libwacom2:amd64 (0.18-1, 0.22-1~ubuntu16.04.1), libdrm-radeon1:amd64 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libdrm-radeon1:i386 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), mesa-vdpau-drivers:amd64 (12.0.6-0ubuntu0.16.04.1, 17.0.7-0ubuntu0.16.04.1), virtualbox-5.1:amd64 (5.1.24-117012~Ubuntu~xenial, 5.1.26-117224~Ubuntu~xenial), gnome-software-common:amd64 (3.20.1+git20170524.0.ea2fe2b0-0ubuntu0.16.04.1, 3.20.5-0ubuntu0.16.04.5), libdrm-dev:amd64 (2.4.70-1~ubuntu16.04.1, 2.4.76-1~ubuntu16.04.1), libwayland-server0:amd64 (1.9.0-1, 1.12.0-1~ubuntu16.04.1), libinput10:amd64 (1.2.3-1ubuntu1, 1.6.3-1ubuntu1~16.04.1), libwayland-cursor0:amd64 (1.9.0-1, 1.12.0-1~ubuntu16.04.1)
End-Date: 2017-07-27  21:35:59