--auth-schemes specifies which authentication schemes are supported on the command line.

--auth-schemes should be a command separated list containing one or more of the following schemes: basic, digest, ntlm, or negotiate.

This will primarily be used to help triage user-reported bugs.

BUG=None
TEST=specify --auth-schemes and ensure that only the specified schemes are supported. Also, when unspecified all schemes should be supported.

Review URL: http://codereview.chromium.org/3199002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@57073 0039d316-1c4b-4281-b951-d872f2087c98