Comment 12 for bug 2019045

More information dump:

* It's easier to see the error Andreas mentioned with --enable-logging=stderr:

--->
[246126:246235:1023/123348.818876:WARNING:obfuscated_file_util.cc(1323)] Failed to get origin+type directory: { uri: filesystem:https://docs.google.com/persistent/docs/fonts/4iCv6KVjbNBYlgoCxCvTsg.woff2, storage key: { origin: https://docs.google.com, top-level site: https://google.com, nonce: <null>, ancestor chain bit: Same-Site } } error:-4
[246126:246235:1023/123348.818941:WARNING:obfuscated_file_util.cc(1323)] Failed to get origin+type directory: { uri: filesystem:https://docs.google.com/persistent/docs/fonts/4iCp6KVjbNBYlgoKejZPsmyN.woff2, storage key: { origin: https://docs.google.com, top-level site: https://google.com, nonce: <null>, ancestor chain bit: Same-Site } } error:-4
<---

I don't quite understand the process there, an uneducated guess: It is trying to fetch a font and then storing it using the filesystem API — which would save it in snap/chromium/common/chromium/Default/File\ Systems but that directory doesn't even exist. Maybe Firefox's implementation differs from Chromium's critically enough to hit this bug. Disabling that with --disable-file-system has no effect.

* Docs uses a remote font instead of a system font because --disable-remote-fonts prevents the Ubuntu font from loading despite it still being listed (the 't' character is a giveaway). This is in line with the error message.

* Since we don't get the problem in Firefox, I tried switching the user agent to Firefox just to see if behavior changed; it didn't.