GitLab

(1) Add generic logstic regression to support preprocessed model.

(2) Also add validation logic in binary classifer to prevent misuse
preprocessed_model with non-preprocessed_model.

Change-Id: Idf3f531c8d7bd45d31a45f6e54be0752a02334d1
Reviewed-on: https://chromium-review.googlesource.com/885541
Commit-Queue: Charles . <charleszhao@chromium.org>
Reviewed-by: Philippe Hamel <hamelphi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532316}