WebFontInfo returns early if there is no match, but it still tries to do FcPatternDestroy on the NULL pointer, which causes a crash.
Created attachment 93469 [details]
Comment on attachment 93469 [details]
I should beat you up for a test.
Re no tests: I don't know how to repro this in a test. I've only seen this happen when there's a problem with the sandbox. I think it will also happen if FontConfig's config files are missing or messed up. It doesn't seem to happen in a normal environment.
Fixed in r86439