It first spams a lot with this:
[3124:1276:0407/085041.535:WARNING:video_receive_stream.cc(487)] No decodable frame in 3000 ms, requesting keyframe.
[3748:5792:0407/085041.547:WARNING:video_receive_stream.cc(487)] No decodable frame in 3000 ms, requesting keyframe.
[3124:1276:0407/085044.535:WARNING:video_receive_stream.cc(487)] No decodable frame in 3000 ms, requesting keyframe.
[3748:5792:0407/085044.548:WARNING:video_receive_stream.cc(487)] No decodable frame in 3000 ms, requesting keyframe.

and then:
[3124:5940:0407/085046.886:ERROR:gpu_video_encode_accelerator_host.cc(226)] Error from OnChannelError(e:\b\c\b\win_builder\src\media\gpu\ipc\client\gpu_video_encode_accelerator_host.cc:69) OnChannelError() (error = 2)
[3748:4692:0407/085046.886:ERROR:gpu_video_encode_accelerator_host.cc(226)] Error from OnChannelError(e:\b\c\b\win_builder\src\media\gpu\ipc\client\gpu_video_encode_accelerator_host.cc:69) OnChannelError() (error = 2)
[3124:5940:0407/085046.886:ERROR:gpu_video_encode_accelerator_host.cc(293)] OnNotifyError error=2
[3748:4692:0407/085046.886:ERROR:gpu_video_encode_accelerator_host.cc(293)] OnNotifyError error=2
[3748:1964:0407/085046.892:WARNING:gpu.cc(111)] Channel encountered error while establishing gpu channel.
[104/115] WebRtcVideoQualityBrowserTests/WebRtcVideoQualityBrowserTest.MANUAL_TestVideoQualityH264/0 (TIMED OUT)


The first build I see it on: https://uberchromegw.corp.google.com/i/chromium.webrtc.fyi/builders/Win10%20Tester/builds/6907/steps/browser_tests/logs/stdio

Recently it started to happen more often.
https://uberchromegw.corp.google.com/i/chromium.webrtc.fyi/builders/Win10%20Tester/builds/6923/steps/browser_tests/logs/stdio
https://uberchromegw.corp.google.com/i/chromium.webrtc.fyi/builders/Win10%20Tester/builds/6946/steps/browser_tests/logs/stdio
https://uberchromegw.corp.google.com/i/chromium.webrtc.fyi/builders/Win10%20Tester/builds/6957/steps/browser_tests/logs/stdio


Sometimes it succeeds after several retries, like here:
https://uberchromegw.corp.google.com/i/chromium.webrtc.fyi/builders/Win10%20Tester/builds/6952/steps/browser_tests/logs/stdio
https://uberchromegw.corp.google.com/i/chromium.webrtc.fyi/builders/Win10%20Tester/builds/6969/steps/browser_tests/logs/stdio