Rename ProtocolInterceptJobFactory and make it not use ProtocolHandlers.
ProtocolHandlers are intended to handle all requests for a particular
scheme, while UrlRequestInterceptors are intended to sit in front of
ProtocolHandlers, and optionally take over handling of any request,
regardless of scheme.
Separating the classes removes some ambiguity and weirdness,
particularly when passing a bunch of interceptors all over the place
from content/ to chrome/ during initialization.
BUG=373800
Review URL: https://codereview.chromium.org/
282103004
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@273874 0039d316-1c4b-4281-b951-d872f2087c98