ntp_tiles: Migrate to multi-observer model

components/ntp_tiles/most_visited_sites_unittest.cc

Index: components/ntp_tiles/most_visited_sites_unittest.cc
diff --git a/components/ntp_tiles/most_visited_sites_unittest.cc b/components/ntp_tiles/most_visited_sites_unittest.cc
index eda087ea002db535843d5cb2cb6078d4f163ec8f..e8b63d8e1ebc07446b8357a1dce56c2f100ccdaa 100644
--- a/components/ntp_tiles/most_visited_sites_unittest.cc
+++ b/components/ntp_tiles/most_visited_sites_unittest.cc
@@ -207,13 +207,7 @@ class MostVisitedSitesTest : public ::testing::Test {
  protected:
   MostVisitedSitesTest()
       : mock_top_sites_(new StrictMock<MockTopSites>()),
-        mock_popular_sites_(new StrictMock<MockPopularSites>()),
-        most_visited_sites_(&pref_service_,
-                            mock_top_sites_,
-                            &mock_suggestions_service_,
-                            base::WrapUnique(mock_popular_sites_),
-                            /*icon_cacher=*/nullptr,
-                            /*supervisor=*/nullptr) {
+        mock_popular_sites_(new StrictMock<MockPopularSites>()) {
     MostVisitedSites::RegisterProfilePrefs(pref_service_.registry());
     // TODO(mastiz): Add test coverage including Popular Sites.
     base::CommandLine::ForCurrentProcess()->AppendSwitch(
@@ -223,6 +217,20 @@ class MostVisitedSitesTest : public ::testing::Test {
     EXPECT_CALL(*mock_popular_sites_, sites())
         .Times(AtLeast(0))
         .WillRepeatedly(ReturnRef(empty_popular_sites_vector_));
+    EXPECT_CALL(mock_suggestions_service_, AddCallback(_))
+        .WillOnce(Invoke(&suggestions_service_callbacks_,
+                         &SuggestionsService::ResponseCallbackList::Add));
+
+    most_visited_sites_ =
+        base::WrapUnique<MostVisitedSites>(new MostVisitedSites(
+            &pref_service_, mock_top_sites_, &mock_suggestions_service_,
+            base::WrapUnique(mock_popular_sites_),
+            /*icon_cacher=*/nullptr,
+            /*supervisor=*/nullptr));
+    most_visited_sites_->AddObserver(&mock_observer_);
+    VerifyAndClearExpectations();
+
+    EXPECT_FALSE(suggestions_service_callbacks_.empty());
   }
 
   bool VerifyAndClearExpectations() {
@@ -245,13 +253,14 @@ class MostVisitedSitesTest : public ::testing::Test {
   StrictMock<MockSuggestionsService> mock_suggestions_service_;
   StrictMock<MockPopularSites>* const mock_popular_sites_;
   StrictMock<MockMostVisitedSitesObserver> mock_observer_;
-  MostVisitedSites most_visited_sites_;
+  std::unique_ptr<MostVisitedSites> most_visited_sites_;
   const PopularSites::SitesVector empty_popular_sites_vector_;
 };
 
-TEST_F(MostVisitedSitesTest, ShouldStartNoCallInConstructor) {
-  // No call to mocks expected by the mere fact of instantiating
-  // MostVisitedSites.
+TEST_F(MostVisitedSitesTest, ShouldRegisterCallbacksInConstructor) {
+  EXPECT_CALL(mock_observer_, OnMostVisitedURLsAvailable(_));
+  suggestions_service_callbacks_.Notify(
+      MakeProfile({MakeSuggestion("Site 1", "http://site1/")}));
   base::RunLoop().RunUntilIdle();
 }
 
@@ -262,9 +271,6 @@ class MostVisitedSitesWithCacheHitTest : public MostVisitedSitesTest {
   MostVisitedSitesWithCacheHitTest() {
     InSequence seq;
     EXPECT_CALL(*mock_top_sites_, SyncWithHistory());
-    EXPECT_CALL(mock_suggestions_service_, AddCallback(_))
-        .WillOnce(Invoke(&suggestions_service_callbacks_,
-                         &SuggestionsService::ResponseCallbackList::Add));
     EXPECT_CALL(mock_suggestions_service_, GetSuggestionsDataFromCache())
         .WillOnce(Return(MakeProfile({
             MakeSuggestion("Site 1", "http://site1/"),
@@ -279,11 +285,12 @@ class MostVisitedSitesWithCacheHitTest : public MostVisitedSitesTest {
                     MatchesTile("Site 2", "http://site2/",
                                 NTPTileSource::SUGGESTIONS_SERVICE),
                     MatchesTile("Site 3", "http://site3/",
+                                NTPTileSource::SUGGESTIONS_SERVICE),
+                    MatchesTile("Site 4", "http://site4/",
                                 NTPTileSource::SUGGESTIONS_SERVICE))));
     EXPECT_CALL(mock_suggestions_service_, FetchSuggestionsData())
         .WillOnce(Return(true));
-    most_visited_sites_.SetMostVisitedURLsObserver(&mock_observer_,
-                                                   /*num_sites=*/3);
+    most_visited_sites_->Refresh();
     VerifyAndClearExpectations();
 
     EXPECT_FALSE(suggestions_service_callbacks_.empty());
@@ -328,20 +335,15 @@ class MostVisitedSitesWithEmptyCacheTest : public MostVisitedSitesTest {
   MostVisitedSitesWithEmptyCacheTest() {
     InSequence seq;
     EXPECT_CALL(*mock_top_sites_, SyncWithHistory());
-    EXPECT_CALL(mock_suggestions_service_, AddCallback(_))
-        .WillOnce(Invoke(&suggestions_service_callbacks_,
-                         &SuggestionsService::ResponseCallbackList::Add));
     EXPECT_CALL(mock_suggestions_service_, GetSuggestionsDataFromCache())
         .WillOnce(Return(SuggestionsProfile()));  // Empty cache.
     EXPECT_CALL(*mock_top_sites_, GetMostVisitedURLs(_, false))
         .WillOnce(Invoke(&top_sites_callbacks_, &TopSitesCallbackList::Add));
     EXPECT_CALL(mock_suggestions_service_, FetchSuggestionsData())
         .WillOnce(Return(true));
-    most_visited_sites_.SetMostVisitedURLsObserver(&mock_observer_,
-                                                   /*num_sites=*/3);
+    most_visited_sites_->Refresh();
     VerifyAndClearExpectations();
 
-    EXPECT_FALSE(suggestions_service_callbacks_.empty());
     EXPECT_FALSE(top_sites_callbacks_.empty());
   }
 };