In 

https://build.chromium.org/p/chromium/builders/Win/builds/42984/steps/compile/logs/stdio

we got the following compile error:

FAILED: obj/media/gpu/ipc/service/media_gpu_ipc_service.gpu_jpeg_decode_accelerator.obj 
ninja -t msvc -e environment.x86 -- C:\b\build\slave\cache\cipd\goma/gomacc "C:\b\depot_tools\win_toolchain\vs_files\95ddda401ec5678f15eeed01d2bee08fcbc5ee97\VC\bin\amd64_x86\cl.exe" /nologo /showIncludes /FC @obj\media\gpu\ipc\service\media_gpu_ipc_service.gpu_jpeg_decode_accelerator.obj.rsp /c ..\..\media\gpu\ipc\service\gpu_jpeg_decode_accelerator.cc /Foobj\media\gpu\ipc\service\media_gpu_ipc_service.gpu_jpeg_decode_accelerator.obj /Fdobj\media\gpu\ipc\media_gpu_ipc_service.cc.pdb 
c:\b\build\slave\win\build\src\media\base\video_codecs.h(11): fatal error C1083: Cannot open include file: 'media/media_features.h': No such file or directory

media/media_features.h is a generated header (from //media:media_features).

There appear to be 9 paths from //media:media_features to //media/gpu/ipc/service and yet somehow the header had not been generated yet.

I do not see the "ACTION //media:media_features" ninja action firing in that build, but I also do not see it in the next build (which ran successfully to completion) so I don't know what to make of this?