GitLab

- Replacing NDEBUG => DCHECK_IS_ON
- Validating match before adding it as a shortcut.

Change-Id: Iaa29faa7cc37c8cf75d833ce8c166c2122d6da55
Reviewed-on: https://chromium-review.googlesource.com/986054
Commit-Queue: Denis Yaroshevskiy <dyaroshev@yandex-team.ru>
Reviewed-by: Kevin Bailey <krb@chromium.org>
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548019}