[iOS] Add FeatureEngagementTracker Viewed Reading List Event Unit Test

Added unit test to verify that -[ReadingListCoordinator start] correctly
sends the "Viewed Reading List" event to the FeatureEngagementTracker.

R=edchin@chromium.org, gchatz@chromium.org, noyau@chromium.org

Bug: 558666
Change-Id: Ib286b0746e773e937881868444ba094bacdc5639
Reviewed-on: https://chromium-review.googlesource.com/569219Reviewed-by: Gregory Chatzinoff <gchatz@chromium.org>
Reviewed-by: Ed Chin <edchin@chromium.org>
Reviewed-by: Eric Noyau <noyau@chromium.org>
Commit-Queue: Cooper Knaak <cooperknaak@google.com>
Cr-Commit-Position: refs/heads/master@{#488021}

ios/chrome/browser/ui/reading_list/BUILD.gn

@@ -120,11 +120,13 @@ source_set("unit_tests") {
     "//base/test:test_support",
     "//components/favicon/core",
     "//components/favicon/core/test:test_support",
+    "//components/feature_engagement_tracker",
     "//components/prefs",
     "//components/reading_list/core",
     "//components/url_formatter",
     "//ios/chrome/browser/browser_state:test_support",
     "//ios/chrome/browser/favicon",
+    "//ios/chrome/browser/feature_engagement_tracker",
     "//ios/chrome/browser/reading_list",
     "//ios/chrome/browser/tabs",
     "//ios/chrome/browser/ui",

ios/chrome/browser/ui/reading_list/reading_list_coordinator_unittest.mm

@@ -9,9 +9,13 @@
 #include "base/time/default_clock.h"
 #include "components/favicon/core/large_icon_service.h"
 #include "components/favicon/core/test/mock_favicon_service.h"
+#include "components/feature_engagement_tracker/public/event_constants.h"
+#include "components/feature_engagement_tracker/public/feature_constants.h"
+#include "components/feature_engagement_tracker/public/feature_engagement_tracker.h"
 #include "components/reading_list/core/reading_list_entry.h"
 #include "components/reading_list/core/reading_list_model_impl.h"
 #include "ios/chrome/browser/browser_state/test_chrome_browser_state.h"
+#include "ios/chrome/browser/feature_engagement_tracker/feature_engagement_tracker_factory.h"
 #include "ios/chrome/browser/reading_list/offline_url_utils.h"
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
 #import "ios/chrome/browser/ui/reading_list/reading_list_collection_view_controller.h"
@@ -22,6 +26,7 @@
 #include "ios/web/public/referrer.h"
 #import "ios/web/public/test/web_test_with_web_state.h"
 #include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
 #import "third_party/ocmock/OCMock/OCMock.h"
 #import "third_party/ocmock/gtest_support.h"
 #include "ui/base/page_transition_types.h"
@@ -95,6 +100,21 @@ using testing::_;
 
 @end
 
+#pragma mark - FeatureEngagementTracker
+namespace {
+
+class FeatureEngagementTrackerStub
+    : public feature_engagement_tracker::FeatureEngagementTracker {
+ public:
+  MOCK_METHOD1(NotifyEvent, void(const std::string&));
+  MOCK_METHOD1(ShouldTriggerHelpUI, bool(const base::Feature& feature));
+  MOCK_METHOD1(Dismissed, void(const base::Feature& feature));
+  MOCK_METHOD0(IsInitialized, bool());
+  MOCK_METHOD1(AddOnInitializedCallback, void(OnInitializedCallback callback));
+};
+
+}  //  namespace
+
 #pragma mark - ReadingListCoordinatorTest
 
 class ReadingListCoordinatorTest : public web::WebTestWithWebState {
@@ -103,6 +123,9 @@ class ReadingListCoordinatorTest : public web::WebTestWithWebState {
     loader_mock_ = [[UrlLoaderStub alloc] init];
 
     TestChromeBrowserState::Builder builder;
+    builder.AddTestingFactory(
+        FeatureEngagementTrackerFactory::GetInstance(),
+        ReadingListCoordinatorTest::BuildFeatureEngagementTrackerStub);
     browser_state_ = builder.Build();
 
     reading_list_model_.reset(new ReadingListModelImpl(
@@ -131,6 +154,8 @@ class ReadingListCoordinatorTest : public web::WebTestWithWebState {
   ReadingListModel* GetReadingListModel() { return reading_list_model_.get(); }
   UrlLoaderStub* GetLoaderStub() { return loader_mock_; }
 
+  ios::ChromeBrowserState* GetBrowserState() { return browser_state_.get(); }
+
   ReadingListCollectionViewController*
   GetAReadingListCollectionViewController() {
     return [[ReadingListCollectionViewController alloc]
@@ -138,6 +163,11 @@ class ReadingListCoordinatorTest : public web::WebTestWithWebState {
                    toolbar:nil];
   }
 
+  static std::unique_ptr<KeyedService> BuildFeatureEngagementTrackerStub(
+      web::BrowserState*) {
+    return base::MakeUnique<FeatureEngagementTrackerStub>();
+  }
+
  private:
   ReadingListCoordinator* coordinator_;
   ReadingListMediator* mediator_;
@@ -229,3 +259,17 @@ TEST_F(ReadingListCoordinatorTest, OpenItemInNewTab) {
   EXPECT_EQ(url, loader.url);
   EXPECT_TRUE(loader.inIncognito);
 }
+
+TEST_F(ReadingListCoordinatorTest, SendViewedReadingListEventInStart) {
+  // Setup.
+  FeatureEngagementTrackerStub* tracker =
+      static_cast<FeatureEngagementTrackerStub*>(
+          FeatureEngagementTrackerFactory::GetForBrowserState(
+              GetBrowserState()));
+
+  // Actions and Tests.
+  EXPECT_CALL(
+      (*tracker),
+      NotifyEvent(feature_engagement_tracker::events::kViewedReadingList));
+  [GetCoordinator() start];
+}