Right now, some URLRequestContexts are built from outside the Network Service. I'm currently moving JSON parsing for Reporting and NEL out of //net and into delegates in //services/network that calls //services/data_decoder, so chromium and content_shell currently need to "borrow" those delegate classes from //services/network.

Once all URLRequestContexts are created by the Network Service, we won't need that layering violation, and can remove the related code and DEPS exceptions.