Remove stale comments

BUG=119595
TBR=jeremy@chromium.org

Review URL: https://codereview.chromium.org/69263003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235834 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235834