OneGoogleBarFetcherImplTest: Shutdown() the GoogleURLTracker before destruction

GoogleURLTracker registers itself as a NetworkChangeObserver at the
NetworkChangeNotifier singleton, and unregisters itself again in Shutdown().
In non-test code, GoogleURLTracker is a KeyedService and so its Shutdown()
gets called at the proper time automatically. But in unit tests that
instantiate it directly, we have to explicitly call Shutdown(),
otherwise we leave behind a dangling pointer.

Bug: 823858
Change-Id: Idc215823ad81c983c8693c04688eccce40f9f26c
Reviewed-on: https://chromium-review.googlesource.com/973603Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545017}

chrome/browser/search/one_google_bar/one_google_bar_fetcher_impl_unittest.cc

@@ -89,6 +89,10 @@ class OneGoogleBarFetcherImplTest : public testing::Test {
                                 api_url_override,
                                 account_consistency_mirror_required) {}
 
+  ~OneGoogleBarFetcherImplTest() override {
+    static_cast<KeyedService&>(google_url_tracker_).Shutdown();
+  }
+
   net::TestURLFetcher* GetRunningURLFetcher() {
     // All created URLFetchers have ID 0 by default.
     net::TestURLFetcher* url_fetcher = url_fetcher_factory_.GetFetcherByID(0);

components/google/core/browser/google_url_tracker.h

@@ -51,6 +51,8 @@ class GoogleURLTracker
   static const char kDefaultGoogleHomepage[];
 
   // Only the GoogleURLTrackerFactory and tests should call this.
+  // Note: In UNIT_TEST_MODE, you *must* manually call Shutdown() before this
+  // instance gets destroyed!
   GoogleURLTracker(std::unique_ptr<GoogleURLTrackerClient> client, Mode mode);
 
   ~GoogleURLTracker() override;