DuplicateFinder isn't actually used by the Scanner, except for one convenience function which we should probably remove, also. BUG= Review-Url: https://codereview.chromium.org/2281443002 Cr-Commit-Position: refs/heads/master@{#38904}
R=rossberg@chromium.org, ulan@chromium.org, vogelheim@chromium.org Review URL: https://codereview.chromium.org/1751863002 Cr-Commit-Position: refs/heads/master@{#34395}