The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5795ebbaa40775bda2ae1046add17ae69ec3ebba

commit 5795ebbaa40775bda2ae1046add17ae69ec3ebba
Author: Catherine Chung <catherinechung@google.com>
Date: Wed Aug 09 08:10:42 2017

Connecting frontend and backend code for the NewTabTracker

- Browsertest added to confirm the tracker can call the promo UI
- Added static helper in NewTabButton to show the promo for the
  last active browser
- The method DismissNewTracker was renamed to OnPromoClosed

Bug: 734132,  737830 
Change-Id: Ia6881474661b44c3994cc641b10333cd96fc1172
Reviewed-on: https://chromium-review.googlesource.com/596274
Commit-Queue: Catherine Chung <catherinechung@google.com>
Reviewed-by: Robert Liao <robliao@chromium.org>
Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492896}
[modify] https://crrev.com/5795ebbaa40775bda2ae1046add17ae69ec3ebba/chrome/browser/feature_engagement/DEPS
[modify] https://crrev.com/5795ebbaa40775bda2ae1046add17ae69ec3ebba/chrome/browser/feature_engagement/new_tab/new_tab_tracker.cc
[modify] https://crrev.com/5795ebbaa40775bda2ae1046add17ae69ec3ebba/chrome/browser/feature_engagement/new_tab/new_tab_tracker.h
[add] https://crrev.com/5795ebbaa40775bda2ae1046add17ae69ec3ebba/chrome/browser/feature_engagement/new_tab/new_tab_tracker_browsertest.cc
[modify] https://crrev.com/5795ebbaa40775bda2ae1046add17ae69ec3ebba/chrome/browser/ui/views/tabs/new_tab_button.cc
[modify] https://crrev.com/5795ebbaa40775bda2ae1046add17ae69ec3ebba/chrome/browser/ui/views/tabs/new_tab_button.h
[modify] https://crrev.com/5795ebbaa40775bda2ae1046add17ae69ec3ebba/chrome/test/BUILD.gn