[NTP Snippets] Refactor background scheduling for remote suggestions

components/ntp_snippets/remote/remote_suggestions_provider_impl_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "components/ntp_snippets/remote/remote_suggestions_provider.h"
+#include "components/ntp_snippets/remote/remote_suggestions_provider_impl.h"
 
 #include <memory>
 #include <utility>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/json/json_reader.h"
 #include "base/macros.h"
@@ skipping 12 matching lines @@
 #include "components/image_fetcher/image_fetcher_delegate.h"
 #include "components/ntp_snippets/category.h"
 #include "components/ntp_snippets/category_info.h"
 #include "components/ntp_snippets/category_rankers/category_ranker.h"
 #include "components/ntp_snippets/category_rankers/constant_category_ranker.h"
 #include "components/ntp_snippets/category_rankers/mock_category_ranker.h"
 #include "components/ntp_snippets/ntp_snippets_constants.h"
 #include "components/ntp_snippets/pref_names.h"
 #include "components/ntp_snippets/remote/ntp_snippet.h"
 #include "components/ntp_snippets/remote/ntp_snippets_fetcher.h"
-#include "components/ntp_snippets/remote/ntp_snippets_scheduler.h"
+#include "components/ntp_snippets/remote/persistent_scheduler.h"
 #include "components/ntp_snippets/remote/remote_suggestions_database.h"
 #include "components/ntp_snippets/remote/test_utils.h"
 #include "components/ntp_snippets/user_classifier.h"
 #include "components/prefs/testing_pref_service.h"
 #include "components/signin/core/browser/fake_profile_oauth2_token_service.h"
 #include "components/signin/core/browser/fake_signin_manager.h"
 #include "components/variations/variations_params_manager.h"
 #include "net/url_request/test_url_fetcher_factory.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/image/image_unittest_util.h"
 
 using image_fetcher::ImageFetcher;
 using image_fetcher::ImageFetcherDelegate;
 using testing::_;
 using testing::ElementsAre;
 using testing::Eq;
 using testing::InSequence;
 using testing::Invoke;
 using testing::IsEmpty;
 using testing::Mock;
 using testing::MockFunction;
 using testing::NiceMock;
 using testing::Not;
 using testing::SaveArg;
 using testing::SizeIs;
 using testing::StartsWith;
+using testing::StrictMock;
 using testing::WithArgs;
 
 namespace ntp_snippets {
 
 namespace {
 
 MATCHER_P(IdEq, value, "") {
   return arg->id() == value;
 }
 
@@ skipping 204 matching lines @@
 
 void ServeOneByOneImage(
     image_fetcher::ImageFetcherDelegate* notify,
     const std::string& id,
     base::Callback<void(const std::string&, const gfx::Image&)> callback) {
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(callback, id, gfx::test::CreateImage(1, 1)));
   notify->OnImageDataFetched(id, "1-by-1-image-data");
 }
 
-gfx::Image FetchImage(RemoteSuggestionsProvider* service,
+gfx::Image FetchImage(RemoteSuggestionsProviderImpl* service,
                       const ContentSuggestion::ID& suggestion_id) {
   gfx::Image result;
   base::RunLoop run_loop;
   service->FetchSuggestionImage(suggestion_id,
                                 base::Bind(
                                     [](base::Closure signal, gfx::Image* output,
                                        const gfx::Image& loaded) {
                                       *output = loaded;
                                       signal.Run();
                                     },
@@ skipping 21 matching lines @@
       int id,
       const GURL& url,
       net::URLFetcher::RequestType request_type,
       net::URLFetcherDelegate* d) override {
     return base::MakeUnique<net::FakeURLFetcher>(
         url, d, /*response_data=*/std::string(), net::HTTP_NOT_FOUND,
         net::URLRequestStatus::FAILED);
   }
 };
 
-class MockScheduler : public NTPSnippetsScheduler {
- public:
-  MOCK_METHOD2(Schedule,
-               bool(base::TimeDelta period_wifi,
-                    base::TimeDelta period_fallback));
-  MOCK_METHOD0(Unschedule, bool());
-};
-
 class MockImageFetcher : public ImageFetcher {
  public:
   MOCK_METHOD1(SetImageFetcherDelegate, void(ImageFetcherDelegate*));
   MOCK_METHOD1(SetDataUseServiceName, void(DataUseServiceName));
   MOCK_METHOD3(
       StartOrQueueNetworkRequest,
       void(const std::string&,
            const GURL&,
            base::Callback<void(const std::string&, const gfx::Image&)>));
 };
@@ skipping 56 matching lines @@
   }
 
   void SetDecodedImage(const gfx::Image& image) { decoded_image_ = image; }
 
  private:
   gfx::Image decoded_image_;
 };
 
 }  // namespace
 
-class RemoteSuggestionsProviderTest : public ::testing::Test {
+class RemoteSuggestionsProviderImplTest : public ::testing::Test {
  public:
-  RemoteSuggestionsProviderTest()
+  RemoteSuggestionsProviderImplTest()
       : params_manager_(ntp_snippets::kStudyName,
                         {{"content_suggestions_backend",
                           kTestContentSuggestionsServerEndpoint},
                          {"fetching_personalization", "non_personal"}}),
         fake_url_fetcher_factory_(
             /*default_factory=*/&failing_url_fetcher_factory_),
         test_url_(kTestContentSuggestionsServerWithAPIKey),
         category_ranker_(base::MakeUnique<ConstantCategoryRanker>()),
         user_classifier_(/*pref_service=*/nullptr),
         image_fetcher_(nullptr),
         image_decoder_(nullptr),
         database_(nullptr) {
-    RemoteSuggestionsProvider::RegisterProfilePrefs(
+    RemoteSuggestionsProviderImpl::RegisterProfilePrefs(
         utils_.pref_service()->registry());
     RequestThrottler::RegisterProfilePrefs(utils_.pref_service()->registry());
 
     EXPECT_TRUE(database_dir_.CreateUniqueTempDir());
   }
 
-  ~RemoteSuggestionsProviderTest() override {
+  ~RemoteSuggestionsProviderImplTest() override {
     // We need to run the message loop after deleting the database, because
     // ProtoDatabaseImpl deletes the actual LevelDB asynchronously on the task
     // runner. Without this, we'd get reports of memory leaks.
     base::RunLoop().RunUntilIdle();
   }
 
   // TODO(vitaliii): Rewrite this function to initialize a test class member
   // instead of creating a new service.
-  std::unique_ptr<RemoteSuggestionsProvider> MakeSnippetsService(
+  std::unique_ptr<RemoteSuggestionsProviderImpl> MakeSnippetsService(
       bool set_empty_response = true) {
     auto service = MakeSnippetsServiceWithoutInitialization();
     WaitForSnippetsServiceInitialization(service.get(), set_empty_response);
     return service;
   }
 
-  std::unique_ptr<RemoteSuggestionsProvider>
+  std::unique_ptr<RemoteSuggestionsProviderImpl>
   MakeSnippetsServiceWithoutInitialization() {
     scoped_refptr<base::SingleThreadTaskRunner> task_runner(
         base::ThreadTaskRunnerHandle::Get());
     scoped_refptr<net::TestURLRequestContextGetter> request_context_getter =
         new net::TestURLRequestContextGetter(task_runner.get());
 
     utils_.ResetSigninManager();
     std::unique_ptr<NTPSnippetsFetcher> snippets_fetcher =
         base::MakeUnique<NTPSnippetsFetcher>(
             utils_.fake_signin_manager(), fake_token_service_.get(),
             std::move(request_context_getter), utils_.pref_service(), nullptr,
             base::Bind(&ParseJson), kAPIKey, &user_classifier_);
 
     utils_.fake_signin_manager()->SignIn("foo@bar.com");
 
     auto image_fetcher = base::MakeUnique<NiceMock<MockImageFetcher>>();
 
     image_fetcher_ = image_fetcher.get();
     EXPECT_CALL(*image_fetcher, SetImageFetcherDelegate(_));
     auto image_decoder = base::MakeUnique<FakeImageDecoder>();
     image_decoder_ = image_decoder.get();
     EXPECT_FALSE(observer_);
     observer_ = base::MakeUnique<FakeContentSuggestionsProviderObserver>();
     auto database = base::MakeUnique<RemoteSuggestionsDatabase>(
         database_dir_.GetPath(), task_runner);
     database_ = database.get();
-    return base::MakeUnique<RemoteSuggestionsProvider>(
+    return base::MakeUnique<RemoteSuggestionsProviderImpl>(
         observer_.get(), utils_.pref_service(), "fr", category_ranker_.get(),
-        &user_classifier_, &scheduler_, std::move(snippets_fetcher),
-        std::move(image_fetcher), std::move(image_decoder), std::move(database),
+        std::move(snippets_fetcher), std::move(image_fetcher),
+        std::move(image_decoder), std::move(database),
         base::MakeUnique<RemoteSuggestionsStatusService>(
             utils_.fake_signin_manager(), utils_.pref_service()));
   }
 
-  void WaitForSnippetsServiceInitialization(RemoteSuggestionsProvider* service,
-                                            bool set_empty_response) {
-    EXPECT_EQ(RemoteSuggestionsProvider::State::NOT_INITED, service->state_);
+  void WaitForSnippetsServiceInitialization(
+      RemoteSuggestionsProviderImpl* service,
+      bool set_empty_response) {
+    EXPECT_EQ(RemoteSuggestionsProviderImpl::State::NOT_INITED,
+              service->state_);
 
     // Add an initial fetch response, as the service tries to fetch when there
     // is nothing in the DB.
     if (set_empty_response) {
       SetUpFetchResponse(GetTestJson(std::vector<std::string>()));
     }
 
     // TODO(treib): Find a better way to wait for initialization to finish.
     base::RunLoop().RunUntilIdle();
-    EXPECT_NE(RemoteSuggestionsProvider::State::NOT_INITED, service->state_);
+    EXPECT_NE(RemoteSuggestionsProviderImpl::State::NOT_INITED,
+              service->state_);
   }
 
-  void ResetSnippetsService(std::unique_ptr<RemoteSuggestionsProvider>* service,
-                            bool set_empty_response) {
+  void ResetSnippetsService(
+      std::unique_ptr<RemoteSuggestionsProviderImpl>* service,
+      bool set_empty_response) {
     service->reset();
     observer_.reset();
     *service = MakeSnippetsService(set_empty_response);
   }
 
   void SetCategoryRanker(std::unique_ptr<CategoryRanker> category_ranker) {
     category_ranker_ = std::move(category_ranker);
   }
 
   ContentSuggestion::ID MakeArticleID(const std::string& id_within_category) {
@@ skipping 12 matching lines @@
   // unknown_category() helpers -- tests can just define their own.
   Category other_category() { return Category::FromRemoteCategory(2); }
 
   Category unknown_category() {
     return Category::FromRemoteCategory(kUnknownRemoteCategoryId);
   }
 
  protected:
   const GURL& test_url() { return test_url_; }
   FakeContentSuggestionsProviderObserver& observer() { return *observer_; }
-  MockScheduler& mock_scheduler() { return scheduler_; }
   // TODO(tschumann): Make this a strict-mock. We want to avoid unneccesary
   // network requests.
   NiceMock<MockImageFetcher>* image_fetcher() { return image_fetcher_; }
   FakeImageDecoder* image_decoder() { return image_decoder_; }
   PrefService* pref_service() { return utils_.pref_service(); }
   RemoteSuggestionsDatabase* database() { return database_; }
 
   // Provide the json to be returned by the fake fetcher.
   void SetUpFetchResponse(const std::string& json) {
     fake_url_fetcher_factory_.SetFakeResponse(test_url_, json, net::HTTP_OK,
                                               net::URLRequestStatus::SUCCESS);
   }
 
   // Have the fake fetcher fail due to a HTTP error like a 404.
   void SetUpHttpError() {
     fake_url_fetcher_factory_.SetFakeResponse(test_url_, /*json=*/std::string(),
                                               net::HTTP_NOT_FOUND,
                                               net::URLRequestStatus::SUCCESS);
   }
 
-  void LoadFromJSONString(RemoteSuggestionsProvider* service,
+  void LoadFromJSONString(RemoteSuggestionsProviderImpl* service,
                           const std::string& json) {
     SetUpFetchResponse(json);
-    service->FetchSnippets(true);
+    service->FetchSnippets(
+        true, std::unique_ptr<RemoteSuggestionsProvider::FetchStatusCallback>(
+                  nullptr));
     base::RunLoop().RunUntilIdle();
   }
 
-  void LoadMoreFromJSONString(RemoteSuggestionsProvider* service,
+  void LoadMoreFromJSONString(RemoteSuggestionsProviderImpl* service,
                               const Category& category,
                               const std::string& json,
                               const std::set<std::string>& known_ids,
                               FetchDoneCallback callback) {
     SetUpFetchResponse(json);
     service->Fetch(category, known_ids, callback);
     base::RunLoop().RunUntilIdle();
   }
 
  private:
   variations::testing::VariationParamsManager params_manager_;
   test::RemoteSuggestionsTestUtils utils_;
   base::MessageLoop message_loop_;
   FailingFakeURLFetcherFactory failing_url_fetcher_factory_;
   // Instantiation of factory automatically sets itself as URLFetcher's factory.
   net::FakeURLFetcherFactory fake_url_fetcher_factory_;
   const GURL test_url_;
   std::unique_ptr<OAuth2TokenService> fake_token_service_;
   std::unique_ptr<CategoryRanker> category_ranker_;
   UserClassifier user_classifier_;
-  NiceMock<MockScheduler> scheduler_;
   std::unique_ptr<FakeContentSuggestionsProviderObserver> observer_;
   NiceMock<MockImageFetcher>* image_fetcher_;
   FakeImageDecoder* image_decoder_;
 
   base::ScopedTempDir database_dir_;
   RemoteSuggestionsDatabase* database_;
 
-  DISALLOW_COPY_AND_ASSIGN(RemoteSuggestionsProviderTest);
+  DISALLOW_COPY_AND_ASSIGN(RemoteSuggestionsProviderImplTest);
 };
 
-TEST_F(RemoteSuggestionsProviderTest, ScheduleOnStart) {
-  // We should get two |Schedule| calls: The first when initialization
-  // completes, the second one after the automatic (since the service doesn't
-  // have any data yet) fetch finishes.
-  EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(2);
-  EXPECT_CALL(mock_scheduler(), Unschedule()).Times(0);
-  auto service = MakeSnippetsService();
-
-  // When we have no snippets are all, loading the service initiates a fetch.
-  EXPECT_EQ("OK", service->snippets_fetcher()->last_status());
-}
-
-TEST_F(RemoteSuggestionsProviderTest, DontRescheduleOnStart) {
-  EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(2);
-  EXPECT_CALL(mock_scheduler(), Unschedule()).Times(0);
-  SetUpFetchResponse(GetTestJson({GetSnippet()}));
-  auto service = MakeSnippetsService(/*set_empty_response=*/false);
-
-  // When recreating the service, we should not get any |Schedule| calls:
-  // The tasks are already scheduled with the correct intervals, so nothing on
-  // initialization, and the service has data from the DB, so no automatic fetch
-  // should happen.
-  Mock::VerifyAndClearExpectations(&mock_scheduler());
-  EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(0);
-  EXPECT_CALL(mock_scheduler(), Unschedule()).Times(0);
-  ResetSnippetsService(&service, /*set_empty_response=*/true);
-}
-
-TEST_F(RemoteSuggestionsProviderTest, RescheduleAfterSuccessfulFetch) {
-  // We should get two |Schedule| calls: The first when initialization
-  // completes, the second one after the automatic (since the service doesn't
-  // have any data yet) fetch finishes.
-  EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(2);
-  auto service = MakeSnippetsService();
-
-  // A successful fetch should trigger another |Schedule|.
-  EXPECT_CALL(mock_scheduler(), Schedule(_, _));
-  LoadFromJSONString(service.get(), GetTestJson({GetSnippet()}));
-}
-
-TEST_F(RemoteSuggestionsProviderTest, DontRescheduleAfterFailedFetch) {
-  // We should get two |Schedule| calls: The first when initialization
-  // completes, the second one after the automatic (since the service doesn't
-  // have any data yet) fetch finishes.
-  EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(2);
-  auto service = MakeSnippetsService();
-
-  // A failed fetch should NOT trigger another |Schedule|.
-  EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(0);
-  LoadFromJSONString(service.get(), GetTestJson({GetInvalidSnippet()}));
-}
-
-TEST_F(RemoteSuggestionsProviderTest, IgnoreRescheduleBeforeInit) {
-  // We should get two |Schedule| calls: The first when initialization
-  // completes, the second one after the automatic (since the service doesn't
-  // have any data yet) fetch finishes.
-  EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(2);
-  // The |RescheduleFetching| call shouldn't do anything (in particular not
-  // result in an |Unschedule|), since the service isn't initialized yet.
-  EXPECT_CALL(mock_scheduler(), Unschedule()).Times(0);
-  auto service = MakeSnippetsServiceWithoutInitialization();
-  service->RescheduleFetching(false);
-  WaitForSnippetsServiceInitialization(service.get(),
-                                       /*set_empty_response=*/true);
-}
-
-TEST_F(RemoteSuggestionsProviderTest, HandleForcedRescheduleBeforeInit) {
-  {
-    InSequence s;
-    // The |RescheduleFetching| call with force=true should result in an
-    // |Unschedule|, since the service isn't initialized yet.
-    EXPECT_CALL(mock_scheduler(), Unschedule()).Times(1);
-    // We should get two |Schedule| calls: The first when initialization
-    // completes, the second one after the automatic (since the service doesn't
-    // have any data yet) fetch finishes.
-    EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(2);
-  }
-  auto service = MakeSnippetsServiceWithoutInitialization();
-  service->RescheduleFetching(true);
-  WaitForSnippetsServiceInitialization(service.get(),
-                                       /*set_empty_response=*/true);
-}
-
-TEST_F(RemoteSuggestionsProviderTest, RescheduleOnStateChange) {
-  {
-    InSequence s;
-    // Initial startup.
-    EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(2);
-    // Service gets disabled.
-    EXPECT_CALL(mock_scheduler(), Unschedule());
-    // Service gets enabled again.
-    EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(2);
-  }
-  auto service = MakeSnippetsService();
-  ASSERT_TRUE(service->ready());
-
-  service->OnStatusChanged(RemoteSuggestionsStatus::ENABLED_AND_SIGNED_IN,
-                           RemoteSuggestionsStatus::EXPLICITLY_DISABLED);
-  ASSERT_FALSE(service->ready());
-  base::RunLoop().RunUntilIdle();
-
-  service->OnStatusChanged(RemoteSuggestionsStatus::EXPLICITLY_DISABLED,
-                           RemoteSuggestionsStatus::ENABLED_AND_SIGNED_OUT);
-  ASSERT_TRUE(service->ready());
-  base::RunLoop().RunUntilIdle();
-}
-
-TEST_F(RemoteSuggestionsProviderTest, DontUnscheduleOnShutdown) {
-  EXPECT_CALL(mock_scheduler(), Schedule(_, _)).Times(2);
-  EXPECT_CALL(mock_scheduler(), Unschedule()).Times(0);
-
-  auto service = MakeSnippetsService();
-
-  service.reset();
-  base::RunLoop().RunUntilIdle();
-}
-
-TEST_F(RemoteSuggestionsProviderTest, Full) {
+TEST_F(RemoteSuggestionsProviderImplTest, Full) {
   std::string json_str(GetTestJson({GetSnippet()}));
 
   auto service = MakeSnippetsService();
 
   LoadFromJSONString(service.get(), json_str);
 
   ASSERT_THAT(observer().SuggestionsForCategory(articles_category()),
               SizeIs(1));
   ASSERT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
 
   const ContentSuggestion& suggestion =
       observer().SuggestionsForCategory(articles_category()).front();
 
   EXPECT_EQ(MakeArticleID(kSnippetUrl), suggestion.id());
   EXPECT_EQ(kSnippetTitle, base::UTF16ToUTF8(suggestion.title()));
   EXPECT_EQ(kSnippetText, base::UTF16ToUTF8(suggestion.snippet_text()));
   EXPECT_EQ(GetDefaultCreationTime(), suggestion.publish_date());
   EXPECT_EQ(kSnippetPublisherName,
             base::UTF16ToUTF8(suggestion.publisher_name()));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, CategoryTitle) {
+TEST_F(RemoteSuggestionsProviderImplTest, CategoryTitle) {
   const base::string16 test_default_title =
       base::UTF8ToUTF16(kTestJsonDefaultCategoryTitle);
 
   // Don't send an initial response -- we want to test what happens without any
   // server status.
   auto service = MakeSnippetsService(/*set_empty_response=*/false);
 
   // The articles category should be there by default, and have a title.
   CategoryInfo info_before = service->GetCategoryInfo(articles_category());
   ASSERT_THAT(info_before.title(), Not(IsEmpty()));
@@ skipping 14 matching lines @@
   // Make sure we updated the title in the CategoryInfo.
   CategoryInfo info_with_title = service->GetCategoryInfo(articles_category());
   EXPECT_THAT(info_before.title(), Not(Eq(info_with_title.title())));
   EXPECT_THAT(test_default_title, Eq(info_with_title.title()));
   EXPECT_THAT(info_before.has_more_action(), Eq(true));
   EXPECT_THAT(info_before.has_reload_action(), Eq(true));
   EXPECT_THAT(info_before.has_view_all_action(), Eq(false));
   EXPECT_THAT(info_before.show_if_empty(), Eq(true));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, MultipleCategories) {
+TEST_F(RemoteSuggestionsProviderImplTest, MultipleCategories) {
   auto service = MakeSnippetsService();
   std::string json_str =
       MultiCategoryJsonBuilder()
           .AddCategory({GetSnippetN(0)}, /*remote_category_id=*/1)
           .AddCategory({GetSnippetN(1)}, /*remote_category_id=*/2)
           .Build();
   LoadFromJSONString(service.get(), json_str);
 
   ASSERT_THAT(observer().statuses(),
               Eq(std::map<Category, CategoryStatus, Category::CompareByID>{
@@ skipping 25 matching lines @@
         observer().SuggestionsForCategory(other_category()).front();
     EXPECT_EQ(MakeOtherID(std::string(kSnippetUrl) + "/1"), suggestion.id());
     EXPECT_EQ(kSnippetTitle, base::UTF16ToUTF8(suggestion.title()));
     EXPECT_EQ(kSnippetText, base::UTF16ToUTF8(suggestion.snippet_text()));
     EXPECT_EQ(GetDefaultCreationTime(), suggestion.publish_date());
     EXPECT_EQ(kSnippetPublisherName,
               base::UTF16ToUTF8(suggestion.publisher_name()));
   }
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ArticleCategoryInfo) {
+TEST_F(RemoteSuggestionsProviderImplTest, ArticleCategoryInfo) {
   auto service = MakeSnippetsService();
   CategoryInfo article_info = service->GetCategoryInfo(articles_category());
   EXPECT_THAT(article_info.has_more_action(), Eq(true));
   EXPECT_THAT(article_info.has_reload_action(), Eq(true));
   EXPECT_THAT(article_info.has_view_all_action(), Eq(false));
   EXPECT_THAT(article_info.show_if_empty(), Eq(true));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ExperimentalCategoryInfo) {
+TEST_F(RemoteSuggestionsProviderImplTest, ExperimentalCategoryInfo) {
   auto service = MakeSnippetsService();
   std::string json_str =
       MultiCategoryJsonBuilder()
           .AddCategory({GetSnippetN(0)}, /*remote_category_id=*/1)
           .AddCategory({GetSnippetN(1)}, kUnknownRemoteCategoryId)
           .Build();
   // Load data with multiple categories so that a new experimental category gets
   // registered.
   LoadFromJSONString(service.get(), json_str);
 
   CategoryInfo info = service->GetCategoryInfo(unknown_category());
   EXPECT_THAT(info.has_more_action(), Eq(false));
   EXPECT_THAT(info.has_reload_action(), Eq(false));
   EXPECT_THAT(info.has_view_all_action(), Eq(false));
   EXPECT_THAT(info.show_if_empty(), Eq(false));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, AddRemoteCategoriesToCategoryRanker) {
+TEST_F(RemoteSuggestionsProviderImplTest, AddRemoteCategoriesToCategoryRanker) {
   auto mock_ranker = base::MakeUnique<MockCategoryRanker>();
   MockCategoryRanker* raw_mock_ranker = mock_ranker.get();
   SetCategoryRanker(std::move(mock_ranker));
   std::string json_str =
       MultiCategoryJsonBuilder()
           .AddCategory({GetSnippetN(0)}, /*remote_category_id=*/11)
           .AddCategory({GetSnippetN(1)}, /*remote_category_id=*/13)
           .AddCategory({GetSnippetN(2)}, /*remote_category_id=*/12)
           .Build();
   SetUpFetchResponse(json_str);
   {
     // The order of categories is determined by the order in which they are
     // added. Thus, the latter is tested here.
     InSequence s;
     EXPECT_CALL(*raw_mock_ranker,
                 AppendCategoryIfNecessary(Category::FromRemoteCategory(11)));
     EXPECT_CALL(*raw_mock_ranker,
                 AppendCategoryIfNecessary(Category::FromRemoteCategory(13)));
     EXPECT_CALL(*raw_mock_ranker,
                 AppendCategoryIfNecessary(Category::FromRemoteCategory(12)));
   }
   auto service = MakeSnippetsService(/*set_empty_response=*/false);
 }
 
-TEST_F(RemoteSuggestionsProviderTest, PersistCategoryInfos) {
+TEST_F(RemoteSuggestionsProviderImplTest, PersistCategoryInfos) {
   auto service = MakeSnippetsService();
   // TODO(vitaliii): Use |articles_category()| instead of constant ID below.
   std::string json_str =
       MultiCategoryJsonBuilder()
           .AddCategoryWithCustomTitle(
               {GetSnippetN(0)}, /*remote_category_id=*/1, "Articles for You")
           .AddCategoryWithCustomTitle({GetSnippetN(1)},
                                       kUnknownRemoteCategoryId, "Other Things")
           .Build();
   LoadFromJSONString(service.get(), json_str);
@@ skipping 24 matching lines @@
 
   CategoryInfo info_articles_after =
       service->GetCategoryInfo(articles_category());
   CategoryInfo info_unknown_after =
       service->GetCategoryInfo(unknown_category());
 
   EXPECT_EQ(info_articles_before.title(), info_articles_after.title());
   EXPECT_EQ(info_unknown_before.title(), info_unknown_after.title());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, PersistRemoteCategoryOrder) {
+TEST_F(RemoteSuggestionsProviderImplTest, PersistRemoteCategoryOrder) {
   // We create a service with a normal ranker to store the order.
   std::string json_str =
       MultiCategoryJsonBuilder()
           .AddCategory({GetSnippetN(0)}, /*remote_category_id=*/11)
           .AddCategory({GetSnippetN(1)}, /*remote_category_id=*/13)
           .AddCategory({GetSnippetN(2)}, /*remote_category_id=*/12)
           .Build();
   SetUpFetchResponse(json_str);
   auto service = MakeSnippetsService(/*set_empty_response=*/false);
 
@@ skipping 15 matching lines @@
     EXPECT_CALL(*raw_mock_ranker,
                 AppendCategoryIfNecessary(Category::FromRemoteCategory(11)));
     EXPECT_CALL(*raw_mock_ranker,
                 AppendCategoryIfNecessary(Category::FromRemoteCategory(13)));
     EXPECT_CALL(*raw_mock_ranker,
                 AppendCategoryIfNecessary(Category::FromRemoteCategory(12)));
   }
   ResetSnippetsService(&service, /*set_empty_response=*/false);
 }
 
-TEST_F(RemoteSuggestionsProviderTest, PersistSuggestions) {
+TEST_F(RemoteSuggestionsProviderImplTest, PersistSuggestions) {
   auto service = MakeSnippetsService();
   std::string json_str =
       MultiCategoryJsonBuilder()
           .AddCategory({GetSnippetN(0)}, /*remote_category_id=*/1)
           .AddCategory({GetSnippetN(2)}, /*remote_category_id=*/2)
           .Build();
   LoadFromJSONString(service.get(), json_str);
 
   ASSERT_THAT(observer().SuggestionsForCategory(articles_category()),
               SizeIs(1));
   ASSERT_THAT(observer().SuggestionsForCategory(other_category()), SizeIs(1));
 
   // Recreate the service to simulate a Chrome restart.
   ResetSnippetsService(&service, /*set_empty_response=*/true);
 
   // The suggestions in both categories should have been restored.
   EXPECT_THAT(observer().SuggestionsForCategory(articles_category()),
               SizeIs(1));
   EXPECT_THAT(observer().SuggestionsForCategory(other_category()), SizeIs(1));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, DontNotifyIfNotAvailable) {
+TEST_F(RemoteSuggestionsProviderImplTest, DontNotifyIfNotAvailable) {
   // Get some suggestions into the database.
   auto service = MakeSnippetsService();
   std::string json_str =
       MultiCategoryJsonBuilder()
           .AddCategory({GetSnippetN(0)},
                        /*remote_category_id=*/1)
           .AddCategory({GetSnippetN(1)}, /*remote_category_id=*/2)
           .Build();
   LoadFromJSONString(service.get(), json_str);
 
   ASSERT_THAT(observer().SuggestionsForCategory(articles_category()),
               SizeIs(1));
   ASSERT_THAT(observer().SuggestionsForCategory(other_category()), SizeIs(1));
 
   service.reset();
 
   // Set the pref that disables remote suggestions.
   pref_service()->SetBoolean(prefs::kEnableSnippets, false);
 
   // Recreate the service to simulate a Chrome start.
   ResetSnippetsService(&service, /*set_empty_response=*/true);
 
-  ASSERT_THAT(RemoteSuggestionsProvider::State::DISABLED, Eq(service->state_));
+  ASSERT_THAT(RemoteSuggestionsProviderImpl::State::DISABLED,
+              Eq(service->state_));
 
   // Now the observer should not have received any suggestions.
   EXPECT_THAT(observer().SuggestionsForCategory(articles_category()),
               IsEmpty());
   EXPECT_THAT(observer().SuggestionsForCategory(other_category()), IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, Clear) {
+TEST_F(RemoteSuggestionsProviderImplTest, Clear) {
   auto service = MakeSnippetsService();
 
   std::string json_str(GetTestJson({GetSnippet()}));
 
   LoadFromJSONString(service.get(), json_str);
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
 
   service->ClearCachedSuggestions(articles_category());
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ReplaceSnippets) {
+TEST_F(RemoteSuggestionsProviderImplTest, ReplaceSnippets) {
   auto service = MakeSnippetsService();
 
   std::string first("http://first");
   LoadFromJSONString(service.get(), GetTestJson({GetSnippetWithUrl(first)}));
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()),
               ElementsAre(IdEq(first)));
 
   std::string second("http://second");
   LoadFromJSONString(service.get(), GetTestJson({GetSnippetWithUrl(second)}));
   // The snippets loaded last replace all that was loaded previously.
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()),
               ElementsAre(IdEq(second)));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, LoadsAdditionalSnippets) {
+TEST_F(RemoteSuggestionsProviderImplTest, LoadsAdditionalSnippets) {
   auto service = MakeSnippetsService();
 
   LoadFromJSONString(service.get(),
                      GetTestJson({GetSnippetWithUrl("http://first")}));
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()),
               ElementsAre(IdEq("http://first")));
 
   auto expect_only_second_suggestion_received = base::Bind([](
       Status status, std::vector<ContentSuggestion> suggestions) {
     EXPECT_THAT(suggestions, SizeIs(1));
@@ skipping 29 matching lines @@
 // The tests TestMergingFetchedMoreSnippetsFillup and
 // TestMergingFetchedMoreSnippetsReplaceAll simulate the following user story:
 // 1) fetch suggestions in NTP A
 // 2) fetch more suggestions in NTP A.
 // 3) open new NTP B: See the last 10 results visible in step 2).
 // 4) fetch more suggestions in NTP B. Make sure no results from step 1) which
 //    were superseded in step 2) get merged back in again.
 // TODO(tschumann): Test step 4) on a higher level instead of peeking into the
 // internal 'dismissed' data. The proper check is to make sure we tell the
 // backend to exclude these snippets.
-TEST_F(RemoteSuggestionsProviderTest, TestMergingFetchedMoreSnippetsFillup) {
+TEST_F(RemoteSuggestionsProviderImplTest,
+       TestMergingFetchedMoreSnippetsFillup) {
   auto service = MakeSnippetsService(/*set_empty_response=*/false);
   LoadFromJSONString(
       service.get(),
       GetTestJson(
           {GetSnippetWithUrl("http://id-1"), GetSnippetWithUrl("http://id-2"),
            GetSnippetWithUrl("http://id-3"), GetSnippetWithUrl("http://id-4"),
            GetSnippetWithUrl("http://id-5"), GetSnippetWithUrl("http://id-6"),
            GetSnippetWithUrl("http://id-7"), GetSnippetWithUrl("http://id-8"),
            GetSnippetWithUrl("http://id-9"),
            GetSnippetWithUrl("http://id-10")}));
@@ skipping 32 matching lines @@
           IdWithinCategoryEq("http://id-5"), IdWithinCategoryEq("http://id-6"),
           IdWithinCategoryEq("http://id-7"), IdWithinCategoryEq("http://id-8"),
           IdWithinCategoryEq("http://id-9"), IdWithinCategoryEq("http://id-10"),
           IdWithinCategoryEq("http://more-id-1"),
           IdWithinCategoryEq("http://more-id-2")));
   // Verify the superseded suggestions got marked as dismissed.
   EXPECT_THAT(service->GetDismissedSnippetsForTesting(articles_category()),
               ElementsAre(IdEq("http://id-1"), IdEq("http://id-2")));
 }
 
-TEST_F(RemoteSuggestionsProviderTest,
+TEST_F(RemoteSuggestionsProviderImplTest,
        TestMergingFetchedMoreSnippetsReplaceAll) {
   auto service = MakeSnippetsService(/*set_empty_response=*/false);
   LoadFromJSONString(
       service.get(),
       GetTestJson(
           {GetSnippetWithUrl("http://id-1"), GetSnippetWithUrl("http://id-2"),
            GetSnippetWithUrl("http://id-3"), GetSnippetWithUrl("http://id-4"),
            GetSnippetWithUrl("http://id-5"), GetSnippetWithUrl("http://id-6"),
            GetSnippetWithUrl("http://id-7"), GetSnippetWithUrl("http://id-8"),
            GetSnippetWithUrl("http://id-9"),
            GetSnippetWithUrl("http://id-10")}));
   EXPECT_THAT(
       observer().SuggestionsForCategory(articles_category()),
       ElementsAre(
           IdWithinCategoryEq("http://id-1"), IdWithinCategoryEq("http://id-2"),
           IdWithinCategoryEq("http://id-3"), IdWithinCategoryEq("http://id-4"),
           IdWithinCategoryEq("http://id-5"), IdWithinCategoryEq("http://id-6"),
           IdWithinCategoryEq("http://id-7"), IdWithinCategoryEq("http://id-8"),
           IdWithinCategoryEq("http://id-9"),
           IdWithinCategoryEq("http://id-10")));
 
   auto expect_receiving_ten_new_snippets =
       base::Bind([](Status status, std::vector<ContentSuggestion> suggestions) {
-        EXPECT_THAT(suggestions, ElementsAre(
-            IdWithinCategoryEq("http://more-id-1"),
-            IdWithinCategoryEq("http://more-id-2"),
-            IdWithinCategoryEq("http://more-id-3"),
-            IdWithinCategoryEq("http://more-id-4"),
-            IdWithinCategoryEq("http://more-id-5"),
-            IdWithinCategoryEq("http://more-id-6"),
-            IdWithinCategoryEq("http://more-id-7"),
-            IdWithinCategoryEq("http://more-id-8"),
-            IdWithinCategoryEq("http://more-id-9"),
-            IdWithinCategoryEq("http://more-id-10")));
+        EXPECT_THAT(suggestions,
+                    ElementsAre(IdWithinCategoryEq("http://more-id-1"),
+                                IdWithinCategoryEq("http://more-id-2"),
+                                IdWithinCategoryEq("http://more-id-3"),
+                                IdWithinCategoryEq("http://more-id-4"),
+                                IdWithinCategoryEq("http://more-id-5"),
+                                IdWithinCategoryEq("http://more-id-6"),
+                                IdWithinCategoryEq("http://more-id-7"),
+                                IdWithinCategoryEq("http://more-id-8"),
+                                IdWithinCategoryEq("http://more-id-9"),
+                                IdWithinCategoryEq("http://more-id-10")));
       });
   LoadMoreFromJSONString(
       service.get(), articles_category(),
       GetTestJson({GetSnippetWithUrl("http://more-id-1"),
                    GetSnippetWithUrl("http://more-id-2"),
                    GetSnippetWithUrl("http://more-id-3"),
                    GetSnippetWithUrl("http://more-id-4"),
                    GetSnippetWithUrl("http://more-id-5"),
                    GetSnippetWithUrl("http://more-id-6"),
                    GetSnippetWithUrl("http://more-id-7"),
@@ skipping 34 matching lines @@
 // Workaround for gMock's lack of support for movable types.
 void SuggestionsLoaded(
     MockFunction<void(Status, const std::vector<ContentSuggestion>&)>* loaded,
     Status status,
     std::vector<ContentSuggestion> suggestions) {
   loaded->Call(status, suggestions);
 }
 
 }  // namespace
 
-TEST_F(RemoteSuggestionsProviderTest, ReturnFetchRequestEmptyBeforeInit) {
+TEST_F(RemoteSuggestionsProviderImplTest, ReturnFetchRequestEmptyBeforeInit) {
   auto service = MakeSnippetsServiceWithoutInitialization();
   MockFunction<void(Status, const std::vector<ContentSuggestion>&)> loaded;
   EXPECT_CALL(loaded, Call(HasCode(StatusCode::TEMPORARY_ERROR), IsEmpty()));
   service->Fetch(articles_category(), std::set<std::string>(),
                  base::Bind(&SuggestionsLoaded, &loaded));
   base::RunLoop().RunUntilIdle();
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ReturnTemporaryErrorForInvalidJson) {
+TEST_F(RemoteSuggestionsProviderImplTest, ReturnTemporaryErrorForInvalidJson) {
   auto service = MakeSnippetsService();
 
   MockFunction<void(Status, const std::vector<ContentSuggestion>&)> loaded;
   EXPECT_CALL(loaded, Call(HasCode(StatusCode::TEMPORARY_ERROR), IsEmpty()));
   LoadMoreFromJSONString(service.get(), articles_category(),
                          "invalid json string}]}",
                          /*known_ids=*/std::set<std::string>(),
                          base::Bind(&SuggestionsLoaded, &loaded));
-  EXPECT_THAT(service->snippets_fetcher()->last_status(),
-              StartsWith("Received invalid JSON"));
+  EXPECT_THAT(
+      service->snippets_fetcher_for_testing_and_debugging()->last_status(),
+      StartsWith("Received invalid JSON"));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ReturnTemporaryErrorForInvalidSnippet) {
+TEST_F(RemoteSuggestionsProviderImplTest,
+       ReturnTemporaryErrorForInvalidSnippet) {
   auto service = MakeSnippetsService();
 
   MockFunction<void(Status, const std::vector<ContentSuggestion>&)> loaded;
   EXPECT_CALL(loaded, Call(HasCode(StatusCode::TEMPORARY_ERROR), IsEmpty()));
   LoadMoreFromJSONString(service.get(), articles_category(),
                          GetTestJson({GetIncompleteSnippet()}),
                          /*known_ids=*/std::set<std::string>(),
                          base::Bind(&SuggestionsLoaded, &loaded));
-  EXPECT_THAT(service->snippets_fetcher()->last_status(),
-              StartsWith("Invalid / empty list"));
+  EXPECT_THAT(
+      service->snippets_fetcher_for_testing_and_debugging()->last_status(),
+      StartsWith("Invalid / empty list"));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ReturnTemporaryErrorForRequestFailure) {
+TEST_F(RemoteSuggestionsProviderImplTest,
+       ReturnTemporaryErrorForRequestFailure) {
   // Created SnippetsService will fail by default with unsuccessful request.
   auto service = MakeSnippetsService(/*set_empty_response=*/false);
 
   MockFunction<void(Status, const std::vector<ContentSuggestion>&)> loaded;
   EXPECT_CALL(loaded, Call(HasCode(StatusCode::TEMPORARY_ERROR), IsEmpty()));
   service->Fetch(articles_category(),
                  /*known_ids=*/std::set<std::string>(),
                  base::Bind(&SuggestionsLoaded, &loaded));
   base::RunLoop().RunUntilIdle();
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ReturnTemporaryErrorForHttpFailure) {
+TEST_F(RemoteSuggestionsProviderImplTest, ReturnTemporaryErrorForHttpFailure) {
   auto service = MakeSnippetsService();
   SetUpHttpError();
 
   MockFunction<void(Status, const std::vector<ContentSuggestion>&)> loaded;
   EXPECT_CALL(loaded, Call(HasCode(StatusCode::TEMPORARY_ERROR), IsEmpty()));
   service->Fetch(articles_category(),
                  /*known_ids=*/std::set<std::string>(),
                  base::Bind(&SuggestionsLoaded, &loaded));
   base::RunLoop().RunUntilIdle();
 }
 
-TEST_F(RemoteSuggestionsProviderTest, LoadInvalidJson) {
+TEST_F(RemoteSuggestionsProviderImplTest, LoadInvalidJson) {
   auto service = MakeSnippetsService();
 
   LoadFromJSONString(service.get(), GetTestJson({GetInvalidSnippet()}));
-  EXPECT_THAT(service->snippets_fetcher()->last_status(),
-              StartsWith("Received invalid JSON"));
+  EXPECT_THAT(
+      service->snippets_fetcher_for_testing_and_debugging()->last_status(),
+      StartsWith("Received invalid JSON"));
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, LoadInvalidJsonWithExistingSnippets) {
+TEST_F(RemoteSuggestionsProviderImplTest, LoadInvalidJsonWithExistingSnippets) {
   auto service = MakeSnippetsService();
 
   LoadFromJSONString(service.get(), GetTestJson({GetSnippet()}));
   ASSERT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
-  ASSERT_EQ("OK", service->snippets_fetcher()->last_status());
+  ASSERT_EQ(
+      "OK",
+      service->snippets_fetcher_for_testing_and_debugging()->last_status());
 
   LoadFromJSONString(service.get(), GetTestJson({GetInvalidSnippet()}));
-  EXPECT_THAT(service->snippets_fetcher()->last_status(),
-              StartsWith("Received invalid JSON"));
+  EXPECT_THAT(
+      service->snippets_fetcher_for_testing_and_debugging()->last_status(),
+      StartsWith("Received invalid JSON"));
   // This should not have changed the existing snippets.
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, LoadIncompleteJson) {
+TEST_F(RemoteSuggestionsProviderImplTest, LoadIncompleteJson) {
   auto service = MakeSnippetsService();
 
   LoadFromJSONString(service.get(), GetTestJson({GetIncompleteSnippet()}));
-  EXPECT_EQ("Invalid / empty list.",
-            service->snippets_fetcher()->last_status());
+  EXPECT_EQ(
+      "Invalid / empty list.",
+      service->snippets_fetcher_for_testing_and_debugging()->last_status());
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, LoadIncompleteJsonWithExistingSnippets) {
+TEST_F(RemoteSuggestionsProviderImplTest,
+       LoadIncompleteJsonWithExistingSnippets) {
   auto service = MakeSnippetsService();
 
   LoadFromJSONString(service.get(), GetTestJson({GetSnippet()}));
   ASSERT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
 
   LoadFromJSONString(service.get(), GetTestJson({GetIncompleteSnippet()}));
-  EXPECT_EQ("Invalid / empty list.",
-            service->snippets_fetcher()->last_status());
+  EXPECT_EQ(
+      "Invalid / empty list.",
+      service->snippets_fetcher_for_testing_and_debugging()->last_status());
   // This should not have changed the existing snippets.
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, Dismiss) {
+TEST_F(RemoteSuggestionsProviderImplTest, Dismiss) {
   auto service = MakeSnippetsService();
 
   std::string json_str(
       GetTestJson({GetSnippetWithSources("http://site.com", "Source 1", "")}));
 
   LoadFromJSONString(service.get(), json_str);
 
   ASSERT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
   // Load the image to store it in the database.
   ServeImageCallback cb =
@@ skipping 30 matching lines @@
   LoadFromJSONString(service.get(), json_str);
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 
   // The snippet can be added again after clearing dismissed snippets.
   service->ClearDismissedSuggestionsForDebugging(articles_category());
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
   LoadFromJSONString(service.get(), json_str);
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, GetDismissed) {
+TEST_F(RemoteSuggestionsProviderImplTest, GetDismissed) {
   auto service = MakeSnippetsService();
 
   LoadFromJSONString(service.get(), GetTestJson({GetSnippet()}));
 
   service->DismissSuggestion(MakeArticleID(kSnippetUrl));
 
   service->GetDismissedSuggestionsForDebugging(
       articles_category(),
       base::Bind(
-          [](RemoteSuggestionsProvider* service,
-             RemoteSuggestionsProviderTest* test,
+          [](RemoteSuggestionsProviderImpl* service,
+             RemoteSuggestionsProviderImplTest* test,
              std::vector<ContentSuggestion> dismissed_suggestions) {
             EXPECT_EQ(1u, dismissed_suggestions.size());
             for (auto& suggestion : dismissed_suggestions) {
               EXPECT_EQ(test->MakeArticleID(kSnippetUrl), suggestion.id());
             }
           },
           service.get(), this));
   base::RunLoop().RunUntilIdle();
 
   // There should be no dismissed snippet after clearing the list.
   service->ClearDismissedSuggestionsForDebugging(articles_category());
   service->GetDismissedSuggestionsForDebugging(
       articles_category(),
       base::Bind(
-          [](RemoteSuggestionsProvider* service,
-             RemoteSuggestionsProviderTest* test,
+          [](RemoteSuggestionsProviderImpl* service,
+             RemoteSuggestionsProviderImplTest* test,
              std::vector<ContentSuggestion> dismissed_suggestions) {
             EXPECT_EQ(0u, dismissed_suggestions.size());
           },
           service.get(), this));
   base::RunLoop().RunUntilIdle();
 }
 
-TEST_F(RemoteSuggestionsProviderTest, CreationTimestampParseFail) {
+TEST_F(RemoteSuggestionsProviderImplTest, CreationTimestampParseFail) {
   auto service = MakeSnippetsService();
 
   std::string json =
       GetSnippetWithTimes(GetDefaultCreationTime(), GetDefaultExpirationTime());
   base::ReplaceFirstSubstringAfterOffset(
       &json, 0, FormatTime(GetDefaultCreationTime()), "aaa1448459205");
   std::string json_str(GetTestJson({json}));
 
   LoadFromJSONString(service.get(), json_str);
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, RemoveExpiredDismissedContent) {
+TEST_F(RemoteSuggestionsProviderImplTest, RemoveExpiredDismissedContent) {
   auto service = MakeSnippetsService();
 
   std::string json_str1(GetTestJson({GetExpiredSnippet()}));
   // Load it.
   LoadFromJSONString(service.get(), json_str1);
   // Load the image to store it in the database.
   // TODO(tschumann): Introduce some abstraction to nicely work with image
   // fetching expectations.
   ServeImageCallback cb =
       base::Bind(&ServeOneByOneImage, &service->GetImageFetcherForTesting());
@@ skipping 12 matching lines @@
   std::string json_str2(GetTestJson({GetSnippetWithUrl(kSnippetUrl2)}));
   LoadFromJSONString(service.get(), json_str2);
 
   EXPECT_THAT(service->GetDismissedSnippetsForTesting(articles_category()),
               IsEmpty());
 
   // Verify the image got removed, too.
   EXPECT_TRUE(FetchImage(service.get(), MakeArticleID(kSnippetUrl)).IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ExpiredContentNotRemoved) {
+TEST_F(RemoteSuggestionsProviderImplTest, ExpiredContentNotRemoved) {
   auto service = MakeSnippetsService();
 
   std::string json_str(GetTestJson({GetExpiredSnippet()}));
 
   LoadFromJSONString(service.get(), json_str);
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, TestSingleSource) {
+TEST_F(RemoteSuggestionsProviderImplTest, TestSingleSource) {
   auto service = MakeSnippetsService();
 
   std::string json_str(GetTestJson({GetSnippetWithSources(
       "http://source1.com", "Source 1", "http://source1.amp.com")}));
 
   LoadFromJSONString(service.get(), json_str);
   ASSERT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
   const NTPSnippet& snippet =
       *service->GetSnippetsForTesting(articles_category()).front();
   EXPECT_EQ(snippet.id(), kSnippetUrl);
   EXPECT_EQ(snippet.url(), GURL("http://source1.com"));
   EXPECT_EQ(snippet.publisher_name(), std::string("Source 1"));
   EXPECT_EQ(snippet.amp_url(), GURL("http://source1.amp.com"));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, TestSingleSourceWithMalformedUrl) {
+TEST_F(RemoteSuggestionsProviderImplTest, TestSingleSourceWithMalformedUrl) {
   auto service = MakeSnippetsService();
 
   std::string json_str(GetTestJson({GetSnippetWithSources(
       "ceci n'est pas un url", "Source 1", "http://source1.amp.com")}));
 
   LoadFromJSONString(service.get(), json_str);
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, TestSingleSourceWithMissingData) {
+TEST_F(RemoteSuggestionsProviderImplTest, TestSingleSourceWithMissingData) {
   auto service = MakeSnippetsService();
 
   std::string json_str(
       GetTestJson({GetSnippetWithSources("http://source1.com", "", "")}));
 
   LoadFromJSONString(service.get(), json_str);
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, LogNumArticlesHistogram) {
+TEST_F(RemoteSuggestionsProviderImplTest, LogNumArticlesHistogram) {
   auto service = MakeSnippetsService();
 
   base::HistogramTester tester;
   LoadFromJSONString(service.get(), GetTestJson({GetInvalidSnippet()}));
 
   EXPECT_THAT(tester.GetAllSamples("NewTabPage.Snippets.NumArticles"),
               ElementsAre(base::Bucket(/*min=*/0, /*count=*/1)));
 
   // Invalid JSON shouldn't contribute to NumArticlesFetched.
   EXPECT_THAT(tester.GetAllSamples("NewTabPage.Snippets.NumArticlesFetched"),
@@ skipping 56 matching lines @@
   // But if there's a non-dismissed snippet in the database, recreating it
   // shouldn't trigger a fetch.
   LoadFromJSONString(
       service.get(),
       GetTestJson({GetSnippetWithUrl("http://not-dismissed.com")}));
   tester.ExpectTotalCount("NewTabPage.Snippets.NumArticlesFetched", 6);
   ResetSnippetsService(&service, /*set_empty_response=*/true);
   tester.ExpectTotalCount("NewTabPage.Snippets.NumArticlesFetched", 6);
 }
 
-TEST_F(RemoteSuggestionsProviderTest, DismissShouldRespectAllKnownUrls) {
+TEST_F(RemoteSuggestionsProviderImplTest, DismissShouldRespectAllKnownUrls) {
   auto service = MakeSnippetsService();
 
   const base::Time creation = GetDefaultCreationTime();
   const base::Time expiry = GetDefaultExpirationTime();
   const std::vector<std::string> source_urls = {
       "http://mashable.com/2016/05/11/stolen",
       "http://www.aol.com/article/2016/05/stolen-doggie"};
   const std::vector<std::string> publishers = {"Mashable", "AOL"};
   const std::vector<std::string> amp_urls = {
       "http://mashable-amphtml.googleusercontent.com/1",
@@ skipping 10 matching lines @@
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 
   // The same article from the AOL domain should now be detected as dismissed.
   LoadFromJSONString(service.get(),
                      GetTestJson({GetSnippetWithUrlAndTimesAndSource(
                          source_urls, source_urls[1], creation, expiry,
                          publishers[1], amp_urls[1])}));
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, StatusChanges) {
+TEST_F(RemoteSuggestionsProviderImplTest, StatusChanges) {
   auto service = MakeSnippetsService();
 
   // Simulate user signed out
   SetUpFetchResponse(GetTestJson({GetSnippet()}));
   service->OnStatusChanged(RemoteSuggestionsStatus::ENABLED_AND_SIGNED_IN,
                            RemoteSuggestionsStatus::SIGNED_OUT_AND_DISABLED);
 
   base::RunLoop().RunUntilIdle();
   EXPECT_THAT(observer().StatusForCategory(articles_category()),
               Eq(CategoryStatus::SIGNED_OUT));
-  EXPECT_THAT(RemoteSuggestionsProvider::State::DISABLED, Eq(service->state_));
+  EXPECT_THAT(RemoteSuggestionsProviderImpl::State::DISABLED,
+              Eq(service->state_));
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()),
               IsEmpty());  // No fetch should be made.
 
   // Simulate user sign in. The service should be ready again and load snippets.
   SetUpFetchResponse(GetTestJson({GetSnippet()}));
   service->OnStatusChanged(RemoteSuggestionsStatus::SIGNED_OUT_AND_DISABLED,
                            RemoteSuggestionsStatus::ENABLED_AND_SIGNED_IN);
   EXPECT_THAT(observer().StatusForCategory(articles_category()),
               Eq(CategoryStatus::AVAILABLE_LOADING));
 
   base::RunLoop().RunUntilIdle();
   EXPECT_THAT(observer().StatusForCategory(articles_category()),
               Eq(CategoryStatus::AVAILABLE));
-  EXPECT_THAT(RemoteSuggestionsProvider::State::READY, Eq(service->state_));
+  EXPECT_THAT(RemoteSuggestionsProviderImpl::State::READY, Eq(service->state_));
   EXPECT_FALSE(service->GetSnippetsForTesting(articles_category()).empty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ImageReturnedWithTheSameId) {
+TEST_F(RemoteSuggestionsProviderImplTest, ImageReturnedWithTheSameId) {
   auto service = MakeSnippetsService();
 
   LoadFromJSONString(service.get(), GetTestJson({GetSnippet()}));
 
   gfx::Image image;
   MockFunction<void(const gfx::Image&)> image_fetched;
   ServeImageCallback cb =
       base::Bind(&ServeOneByOneImage, &service->GetImageFetcherForTesting());
   {
     InSequence s;
     EXPECT_CALL(*image_fetcher(), StartOrQueueNetworkRequest(_, _, _))
         .WillOnce(WithArgs<0, 2>(Invoke(&cb, &ServeImageCallback::Run)));
     EXPECT_CALL(image_fetched, Call(_)).WillOnce(SaveArg<0>(&image));
   }
 
   service->FetchSuggestionImage(
       MakeArticleID(kSnippetUrl),
       base::Bind(&MockFunction<void(const gfx::Image&)>::Call,
                  base::Unretained(&image_fetched)));
   base::RunLoop().RunUntilIdle();
   // Check that the image by ServeOneByOneImage is really served.
   EXPECT_EQ(1, image.Width());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, EmptyImageReturnedForNonExistentId) {
+TEST_F(RemoteSuggestionsProviderImplTest, EmptyImageReturnedForNonExistentId) {
   auto service = MakeSnippetsService();
 
   // Create a non-empty image so that we can test the image gets updated.
   gfx::Image image = gfx::test::CreateImage(1, 1);
   MockFunction<void(const gfx::Image&)> image_fetched;
   EXPECT_CALL(image_fetched, Call(_)).WillOnce(SaveArg<0>(&image));
 
   service->FetchSuggestionImage(
       MakeArticleID(kSnippetUrl2),
       base::Bind(&MockFunction<void(const gfx::Image&)>::Call,
                  base::Unretained(&image_fetched)));
 
   base::RunLoop().RunUntilIdle();
   EXPECT_TRUE(image.IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest,
+TEST_F(RemoteSuggestionsProviderImplTest,
        FetchingUnknownImageIdShouldNotHitDatabase) {
   // Testing that the provider is not accessing the database is tricky.
   // Therefore, we simply put in some data making sure that if the provider asks
   // the database, it will get a wrong answer.
   auto service = MakeSnippetsService();
 
   ContentSuggestion::ID unknown_id = MakeArticleID(kSnippetUrl2);
   database()->SaveImage(unknown_id.id_within_category(), "some image blob");
   // Set up the image decoder to always return the 1x1 test image.
   image_decoder()->SetDecodedImage(gfx::test::CreateImage(1, 1));
 
   // Create a non-empty image so that we can test the image gets updated.
   gfx::Image image = gfx::test::CreateImage(2, 2);
   MockFunction<void(const gfx::Image&)> image_fetched;
   EXPECT_CALL(image_fetched, Call(_)).WillOnce(SaveArg<0>(&image));
 
   service->FetchSuggestionImage(
       MakeArticleID(kSnippetUrl2),
       base::Bind(&MockFunction<void(const gfx::Image&)>::Call,
                  base::Unretained(&image_fetched)));
 
   base::RunLoop().RunUntilIdle();
   EXPECT_TRUE(image.IsEmpty()) << "got image with width: " << image.Width();
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ClearHistoryRemovesAllSuggestions) {
+TEST_F(RemoteSuggestionsProviderImplTest, ClearHistoryRemovesAllSuggestions) {
   auto service = MakeSnippetsService();
 
   std::string first_snippet = GetSnippetWithUrl("http://url1.com");
   std::string second_snippet = GetSnippetWithUrl("http://url2.com");
   std::string json_str = GetTestJson({first_snippet, second_snippet});
   LoadFromJSONString(service.get(), json_str);
   ASSERT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(2));
 
   service->DismissSuggestion(MakeArticleID("http://url1.com"));
   ASSERT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
   ASSERT_THAT(service->GetDismissedSnippetsForTesting(articles_category()),
               SizeIs(1));
 
   base::Time begin = base::Time::FromTimeT(123),
              end = base::Time::FromTimeT(456);
   base::Callback<bool(const GURL& url)> filter;
   service->ClearHistory(begin, end, filter);
 
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
   EXPECT_THAT(service->GetDismissedSnippetsForTesting(articles_category()),
               IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest, SuggestionsFetchedOnSignInAndSignOut) {
+TEST_F(RemoteSuggestionsProviderImplTest,
+       SuggestionsFetchedOnSignInAndSignOut) {
   auto service = MakeSnippetsService();
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), IsEmpty());
 
   // |MakeSnippetsService()| creates a service where user is signed in already,
   // so we start by signing out.
   SetUpFetchResponse(GetTestJson({GetSnippetN(1)}));
   service->OnStatusChanged(RemoteSuggestionsStatus::ENABLED_AND_SIGNED_IN,
                            RemoteSuggestionsStatus::ENABLED_AND_SIGNED_OUT);
   base::RunLoop().RunUntilIdle();
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(1));
 
   // Sign in to check a transition from signed out to signed in.
   SetUpFetchResponse(GetTestJson({GetSnippetN(1), GetSnippetN(2)}));
   service->OnStatusChanged(RemoteSuggestionsStatus::ENABLED_AND_SIGNED_OUT,
                            RemoteSuggestionsStatus::ENABLED_AND_SIGNED_IN);
   base::RunLoop().RunUntilIdle();
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()), SizeIs(2));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, ShouldClearOrphanedImagesOnRestart) {
+TEST_F(RemoteSuggestionsProviderImplTest, ShouldClearOrphanedImagesOnRestart) {
   auto service = MakeSnippetsService();
 
   LoadFromJSONString(service.get(), GetTestJson({GetSnippet()}));
   ServeImageCallback cb =
       base::Bind(&ServeOneByOneImage, &service->GetImageFetcherForTesting());
 
   EXPECT_CALL(*image_fetcher(), StartOrQueueNetworkRequest(_, _, _))
       .WillOnce(WithArgs<0, 2>(Invoke(&cb, &ServeImageCallback::Run)));
   image_decoder()->SetDecodedImage(gfx::test::CreateImage(1, 1));
 
   gfx::Image image = FetchImage(service.get(), MakeArticleID(kSnippetUrl));
   EXPECT_EQ(1, image.Width());
   EXPECT_FALSE(image.IsEmpty());
 
   // Send new suggestion which don't include the snippet referencing the image.
   LoadFromJSONString(service.get(),
                      GetTestJson({GetSnippetWithUrl(
                          "http://something.com/pletely/unrelated")}));
   // The image should still be available until a restart happens.
   EXPECT_FALSE(FetchImage(service.get(), MakeArticleID(kSnippetUrl)).IsEmpty());
   ResetSnippetsService(&service, /*set_empty_response=*/true);
   // After the restart, the image should be garbage collected.
   EXPECT_TRUE(FetchImage(service.get(), MakeArticleID(kSnippetUrl)).IsEmpty());
 }
 
-TEST_F(RemoteSuggestionsProviderTest,
+TEST_F(RemoteSuggestionsProviderImplTest,
        ShouldHandleMoreThanMaxSnippetsInResponse) {
   auto service = MakeSnippetsService();
 
   std::vector<std::string> suggestions;
   for (int i = 0; i < service->GetMaxSnippetCountForTesting() + 1; ++i) {
     suggestions.push_back(GetSnippetWithUrl(
         base::StringPrintf("http://localhost/snippet-id-%d", i)));
   }
   LoadFromJSONString(service.get(), GetTestJson(suggestions));
   // TODO(tschumann): We should probably trim out any additional results and
   // only serve the MaxSnippetCount items.
   EXPECT_THAT(service->GetSnippetsForTesting(articles_category()),
               SizeIs(service->GetMaxSnippetCountForTesting() + 1));
 }
 
-TEST_F(RemoteSuggestionsProviderTest, StoreLastSuccessfullBackgroundFetchTime) {
-  // On initialization of the RemoteSuggestionsProvider a background fetch is
-  // triggered since the snippets DB is empty. Therefore the service must not be
-  // initialized until the test clock is set.
+TEST_F(RemoteSuggestionsProviderImplTest,
+       StoreLastSuccessfullBackgroundFetchTime) {
+  // On initialization of the RemoteSuggestionsProviderImpl a background fetch
+  // is triggered since the snippets DB is empty. Therefore the service must not
+  // be initialized until the test clock is set.
   auto service = MakeSnippetsServiceWithoutInitialization();
 
   auto simple_test_clock = base::MakeUnique<base::SimpleTestClock>();
   base::SimpleTestClock* simple_test_clock_ptr = simple_test_clock.get();
   service->SetClockForTesting(std::move(simple_test_clock));
 
   // Test that the preference is correctly initialized with the default value 0.
   EXPECT_EQ(
       0, pref_service()->GetInt64(prefs::kLastSuccessfulBackgroundFetchTime));
 
   WaitForSnippetsServiceInitialization(service.get(),
                                        /*set_empty_response=*/true);
   EXPECT_EQ(
       simple_test_clock_ptr->Now().ToInternalValue(),
       pref_service()->GetInt64(prefs::kLastSuccessfulBackgroundFetchTime));
 
   // Advance the time and check whether the time was updated correctly after the
   // background fetch.
   simple_test_clock_ptr->Advance(TimeDelta::FromHours(1));
-  service->FetchSnippetsInTheBackground();
+  service->RefetchInTheBackground(
+      std::unique_ptr<RemoteSuggestionsProvider::FetchStatusCallback>(nullptr));
   base::RunLoop().RunUntilIdle();
+  // TODO(jkrcal): Move together with the pref storage into the scheduler.
   EXPECT_EQ(
       simple_test_clock_ptr->Now().ToInternalValue(),
       pref_service()->GetInt64(prefs::kLastSuccessfulBackgroundFetchTime));
   // TODO(markusheintz): Add a test that simulates a browser restart once the
   // scheduler refactoring is done (crbug.com/672434).
 }
 
+TEST_F(RemoteSuggestionsProviderImplTest, CallsProviderStatusCallbackIfReady) {
+  // Initiate the service so that it is already READY.
+  auto service = MakeSnippetsService();
+
+  StrictMock<MockFunction<void(RemoteSuggestionsProvider::ProviderStatus)>>
+      status_callback;
+  // The callback should be called on registering.
+  EXPECT_CALL(status_callback,
+              Call(RemoteSuggestionsProvider::ProviderStatus::ACTIVE));
+  service->SetProviderStatusCallback(
+      base::MakeUnique<RemoteSuggestionsProvider::ProviderStatusCallback>(
+          base::Bind(&MockFunction<void(
+                         RemoteSuggestionsProvider::ProviderStatus)>::Call,
+                     base::Unretained(&status_callback))));
+}
+
+TEST_F(RemoteSuggestionsProviderImplTest,
+       DoesNotCallProviderStatusCallbackIfNotInited) {
+  auto service = MakeSnippetsServiceWithoutInitialization();
+
+  StrictMock<MockFunction<void(RemoteSuggestionsProvider::ProviderStatus)>>
+      status_callback;
+  // The provider is not initialized yet, no callback should be called on
+  // registering.
+  service->SetProviderStatusCallback(
+      base::MakeUnique<RemoteSuggestionsProvider::ProviderStatusCallback>(
+          base::Bind(&MockFunction<void(
+                         RemoteSuggestionsProvider::ProviderStatus)>::Call,
+                     base::Unretained(&status_callback))));
+}
+
+TEST_F(RemoteSuggestionsProviderImplTest,
+       CallsProviderStatusCallbackWhenReady) {
+  auto service = MakeSnippetsServiceWithoutInitialization();
+  StrictMock<MockFunction<void(RemoteSuggestionsProvider::ProviderStatus)>>
+      status_callback;
+  service->SetProviderStatusCallback(
+      base::MakeUnique<RemoteSuggestionsProvider::ProviderStatusCallback>(
+          base::Bind(&MockFunction<void(
+                         RemoteSuggestionsProvider::ProviderStatus)>::Call,
+                     base::Unretained(&status_callback))));
+
+  // Should be called when becoming ready.
+  EXPECT_CALL(status_callback,
+              Call(RemoteSuggestionsProvider::ProviderStatus::ACTIVE));
+  WaitForSnippetsServiceInitialization(service.get(),
+                                       /*set_empty_response=*/true);
+}
+
+TEST_F(RemoteSuggestionsProviderImplTest, CallsProviderStatusCallbackOnError) {
+  auto service = MakeSnippetsServiceWithoutInitialization();
+  StrictMock<MockFunction<void(RemoteSuggestionsProvider::ProviderStatus)>>
+      status_callback;
+  service->SetProviderStatusCallback(
+      base::MakeUnique<RemoteSuggestionsProvider::ProviderStatusCallback>(
+          base::Bind(&MockFunction<void(
+                         RemoteSuggestionsProvider::ProviderStatus)>::Call,
+                     base::Unretained(&status_callback))));
+
+  // Should be called on error.
+  EXPECT_CALL(status_callback,
+              Call(RemoteSuggestionsProvider::ProviderStatus::INACTIVE));
+  service->EnterState(RemoteSuggestionsProviderImpl::State::ERROR_OCCURRED);
+}
+
+TEST_F(RemoteSuggestionsProviderImplTest,
+       CallsProviderStatusCallbackWhenDisabled) {
+  auto service = MakeSnippetsServiceWithoutInitialization();
+  StrictMock<MockFunction<void(RemoteSuggestionsProvider::ProviderStatus)>>
+      status_callback;
+  service->SetProviderStatusCallback(
+      base::MakeUnique<RemoteSuggestionsProvider::ProviderStatusCallback>(
+          base::Bind(&MockFunction<void(
+                         RemoteSuggestionsProvider::ProviderStatus)>::Call,
+                     base::Unretained(&status_callback))));
+
+  // Should be called when becoming disabled.
+  EXPECT_CALL(status_callback,
+              Call(RemoteSuggestionsProvider::ProviderStatus::INACTIVE));
+  service->EnterState(RemoteSuggestionsProviderImpl::State::DISABLED);
+}
+
 }  // namespace ntp_snippets