Remove a few dead fields.

No functionality change. Found by scythe.

BUG=
R=asanka@chromium.org, thestig@chromium.org

Review URL: https://codereview.chromium.org/139293005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245019 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245019