Add feature to control Focus on Omnibox in incognito tab intents.

Incognito tab launcher intents are followed by focus on Omnibox and
partially hiding incognito NTP message and totally hiding incognito
tab counter.
This behavior is moved behind "kFocusOnOmniboxInIncognitoTabIntents"
feature. The feature is disabled by default until appropriate privacy
notice is added.

Bug: 1029018
Change-Id: I9e1152b747f6d0d02aa6e31263a36c345ff77dab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1941309
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Peter Conn <peconn@chromium.org>
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Cr-Commit-Position: refs/heads/master@{#720869}
6 files changed