GitLab

(1) Normalizer rescale a int32 or float feature by diving the
    normalizer.

(2) Convert_to_string preprocessor sets a feature from int32 or bool
    to string_value.

BUG=786472

Change-Id: Ia93bbb7a28be4fdd22a6d72e83c86852878bc0a6
Reviewed-on: https://chromium-review.googlesource.com/1001085
Commit-Queue: Charles . <charleszhao@chromium.org>
Reviewed-by: Andrew Moylan <amoylan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549797}