Add and update prefs for search engine promo

Add and update prefs for search engine promo

- Adds new shared pref key and values for search engine promo state
- Exposes prevous promo type features in ChromeFeatureList to java

BUG=712833, 712836
Review-Url: https://codereview.chromium.org/2848333002
Cr-Commit-Position: refs/heads/master@{#468458}
Committed: https://chromium.googlesource.com/chromium/src/+/9e88ce2b0296bc72489bf3f78a23da8d310d29e2

[Yusuf, 2017-05-01 19:33:07]

yusufo@chromium.org changed reviewers:
+ dfalcantara@chromium.org

[gone, 2017-05-01 21:48:29]

lgtm

[gone, 2017-05-01 21:48:34]

The CQ bit was checked by dfalcantara@chromium.org

[commit-bot: I haz the power, 2017-05-01 21:49:34]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-01 22:31:09]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493675314957320, "parent_rev":
"a561de6d59f43481c46e61a34508fa15c5fd2abd", "commit_rev":
"9e88ce2b0296bc72489bf3f78a23da8d310d29e2"}

[commit-bot: I haz the power, 2017-05-01 22:31:19]

Description was changed from

==========
Add and update prefs for search engine promo

- Adds new shared pref key and values for search engine promo state
- Exposes prevous promo type features in ChromeFeatureList to java

BUG=712833, 712836
==========

to

==========
Add and update prefs for search engine promo

- Adds new shared pref key and values for search engine promo state
- Exposes prevous promo type features in ChromeFeatureList to java

BUG=712833, 712836

Review-Url: https://codereview.chromium.org/2848333002
Cr-Commit-Position: refs/heads/master@{#468458}
Committed:
https://chromium.googlesource.com/chromium/src/+/9e88ce2b0296bc72489bf3f78a23...
==========

[commit-bot: I haz the power, 2017-05-01 22:31:20]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/9e88ce2b0296bc72489bf3f78a23...