At a simple level, the variables from net/net.gypi need to be inlined into BUILD.gn.

This is more tricky some some of these lists seem to be autogenerated by a script net/data/update_net_gypi.py

On a related note, the network build is pretty out-of-control. The obviuos cleanup is to make many separate build files for the different components, so that //net would conditionally depend on //net/websockets instead of having //net have a huge list of all websocket files inline. However, the dependencies may be too tangled to make a proper DAG out of the build