When using Xorg, it seems Chromium runs as expected:

-------------------[ chromium_capture_logs_h264_video ]--------------------
ID: com.canonical.certification::chromium_capture_logs_h264_video
--------------------------------------------------------------------------------
Gtk-Message: 15:18:04.344: Failed to load module "canberra-gtk-module"
Gtk-Message: 15:18:04.345: Failed to load module "canberra-gtk-module"
[34312:34312:0928/151804.364289:WARNING:account_consistency_mode_manager.cc(70)] Desktop Identity Consistency cannot be enabled as no OAuth client ID and client secret have been configured.
[34414:34414:0928/151804.441314:WARNING:sandbox_linux.cc(376)] InitializeSandbox() called with multiple threads in process gpu-process.
WARNING: Kernel has no file descriptor comparison support: Operation not permitted
[34312:34312:0928/151804.467334:WARNING:bluez_dbus_manager.cc(247)] Floss manager not present, cannot set Floss enable/disable.
[34445:14:0928/151804.569470:INFO:decoder.cc(41)] DecryptingVideoDecoder
[34414:34651:0928/151804.570643:INFO:decoder.cc(65)] VDAVideoDecoder
[34445:14:0928/151804.572488:INFO:decoder.cc(65)] VDAVideoDecoder
[34445:14:0928/151804.572607:INFO:decoder.cc(65)] VDAVideoDecoder
[34312:34400:0928/151806.556642:ERROR:udev_watcher.cc(98)] Failed to begin udev enumeration.
[34312:34312:0928/151815.191042:WARNING:zygote_communication_linux.cc(285)] Error reading message from zygote: Connection reset by peer (104)
[34312:34312:0928/151815.193255:ERROR:zygote_communication_linux.cc(275)] Failed to send GetTerminationStatus message to zygote
[34312:34312:0928/151815.193270:WARNING:zygote_communication_linux.cc(287)] Socket closed prematurely.
--------------------------------------------------------------------------------
Outcome: job passed
-----------------------------[ Running job 2 / 8 ]------------------------------
------------[ chromium_capture_logs_h264_video_vaapi_disabled ]------------
ID: com.canonical.certification::chromium_capture_logs_h264_video_vaapi_disabled
--------------------------------------------------------------------------------
Gtk-Message: 15:18:16.067: Failed to load module "canberra-gtk-module"
Gtk-Message: 15:18:16.068: Failed to load module "canberra-gtk-module"
[34682:34682:0928/151816.084974:WARNING:account_consistency_mode_manager.cc(70)] Desktop Identity Consistency cannot be enabled as no OAuth client ID and client secret have been configured.
[34788:34788:0928/151816.137342:WARNING:sandbox_linux.cc(376)] InitializeSandbox() called with multiple threads in process gpu-process.
WARNING: Kernel has no file descriptor comparison support: Operation not permitted
[34682:34682:0928/151816.191534:WARNING:bluez_dbus_manager.cc(247)] Floss manager not present, cannot set Floss enable/disable.
[34827:14:0928/151816.265405:INFO:decoder.cc(41)] DecryptingVideoDecoder
[34827:14:0928/151816.265578:INFO:decoder.cc(32)] VpxVideoDecoder
[34827:14:0928/151816.265780:INFO:decoder.cc(44)] Dav1dVideoDecoder
[34827:14:0928/151816.266935:INFO:decoder.cc(29)] FFmpegVideoDecoder
[34827:14:0928/151816.267012:INFO:decoder.cc(29)] FFmpegVideoDecoder
[34682:34799:0928/151818.281582:ERROR:udev_watcher.cc(98)] Failed to begin udev enumeration.
[34682:34682:0928/151826.909057:WARNING:zygote_communication_linux.cc(285)] Error reading message from zygote: Connection reset by peer (104)
[34682:34682:0928/151826.910093:ERROR:zygote_communication_linux.cc(275)] Failed to send GetTerminationStatus message to zygote
[34682:34682:0928/151826.910106:WARNING:zygote_communication_linux.cc(287)] Socket closed prematurely.
--------------------------------------------------------------------------------
Outcome: job passed