Support for an "unlinked" dependency is something that would aid modularization of Chrome code.

There are alternate, hacky ways to work around this, but they aren't ideal.  Ultimately, we'll have to assess whether some extra complexity in GN is worthwhile to reduce complexity of a module's GN build file.

More details are here:

https://docs.google.com/document/d/184glBHRbAuc03msDzow1oEqXhM1A0en1BxJOqN1tfuQ/edit