GlobalDescriptors::Get/MaybeGet seem generally dangerous. I did a quick codesearch, and there's quite a few places where ownership of the FDs is taken without GlobalDescriptors knowing (sometimes by multiple owners, e.g. https://cs.chromium.org/chromium/src/chromecast/app/cast_main_delegate.cc?q=%22base::File(%22&sq=package:chromium&l=200&dr=C)