PlzNavigate: Refactoring unit tests to use NavigationSimulator

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

Bug: 728571
Change-Id: I6d87af439398bed003f7993ed8e4ab58f8702b40
Reviewed-on: https://chromium-review.googlesource.com/638570
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@{#498761}
1 file changed