chromium/services/network/url_loader.md

# URLLoader
TODO(loading-dev): Write brief description about URLLoaderFactory, URLLoader and
URLLoaderClient.

A deck that explains how Mojo connections for these URLLoader classes can be
established to issue a network request with diagrams:
https://docs.google.com/presentation/d/1ku7pkh09h6sQ6epudsVvHehRzvanAU7ckzfiVvMoljo/edit?usp=sharing