GitLab

This CL adjusts the logic of merging prepopulated data into search
engines. The goal is to preserve Play API search engine record.The
behavior should be:
- When new prepopulated engine matches Play API engine, merge them.
- When prepopulated Play API engine gets updated, apply updates.
- When prepopulated Play API engine gets removed, keep the record.

BUG=1002271
R=pkasting@chromium.org,wylieb@chromium.org

Change-Id: I75822512bde4024f32af24565d66d87158732cbf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1814642Reviewed-by: Kevin Bailey <krb@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Brandon Wylie <wylieb@chromium.org>
Commit-Queue: Pavel Yatsuk <pavely@chromium.org>
Cr-Commit-Position: refs/heads/master@{#698634}