Fix a crash when downloading invalid client certificates.

      Additionally, remove some outdated comments/TODOs that no longer apply.

BUG=112451


Review URL: http://codereview.chromium.org/9361007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@120991 0039d316-1c4b-4281-b951-d872f2087c98