Domain Reliability: Don't send proxy address, other fixes

Make sure the monitor does not collect the proxy's address if one was used.
(In the process, refactor RequestInfo to contain the whole HttpResponseInfo,
tighten up OnRequestLegComplete, and poke at unittests a bit.)

Also, count network errors as well as HTTP errors as failures (!).

BUG=356791

Review URL: https://codereview.chromium.org/267633002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269657 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed