Building unit tests.

I have been able to build chromium for linux, on Ubuntu using this guide:

Subsequently, I want to build unit tests.

Specifically, I want to build vaapi_unittest.

But doing so, fails for me. First it failed on missing TTF fonts, but adding those to third_party/test_fonts/test_fonts/ I now get: generate_fontconfig_caches failed with exit code 1

$ autoninja vaapi_unittest
[25/1011] CXX obj/ui/base/x/x/x11_util.o
…
[789/1009] ACTION //third_party/test_fonts/fontconfig:do_generate_fontconfig_caches(//build/toolchain/linux:clang_x64)
FAILED: fontconfig_caches/fb5c91b2895aa445d23aebf7f9e2189c-le64.cache-7
python3 ../../build/gn_run_binary.py generate_fontconfig_caches
generate_fontconfig_caches failed with exit code 1
[802/1009] CXX obj/media/gpu/chromeos/chromeos/video_decoder_pipeline.o
ninja: build stopped: subcommand failed.

Two questions:

1)  What makes the commadn fail.

2) I am surprised that vaapi_unittest could depend on fonts. How do I remove that dependency, and try building without fonts?

Thanks!