PlzNavigate: Refactoring unit tests to use NavigationSimulator

Removed all usage of WebContentsTester::TestDidNavigate in
site_engagement_service_unittest.cc.

Bug: 728571
Change-Id: I4e1deef8ea856b7ad78e8170fea009443d90531a
Reviewed-on: https://chromium-review.googlesource.com/638274
Reviewed-by: Camille Lamy <clamy@chromium.org>
Reviewed-by: Ben Wells <benwells@chromium.org>
Commit-Queue: Arthur Hemery <ahemery@chromium.org>
Cr-Commit-Position: refs/heads/master@{#498405}
1 file changed