Create skeleton for the Prefetching store and initial pipeline step.

components/offline_pages/content/suggested_articles_observer_unittest.cc

Index: components/offline_pages/content/suggested_articles_observer_unittest.cc
diff --git a/components/offline_pages/content/suggested_articles_observer_unittest.cc b/components/offline_pages/content/suggested_articles_observer_unittest.cc
index 6fae70d85ce8c4c5ddd046dbfd82ffb3c4b1b359..0ab41ac109cfbfdb23c40ab3b395d5116358d33e 100644
--- a/components/offline_pages/content/suggested_articles_observer_unittest.cc
+++ b/components/offline_pages/content/suggested_articles_observer_unittest.cc
@@ -32,31 +32,39 @@ class TestingPrefetchDispatcher : public PrefetchDispatcher {
  public:
   TestingPrefetchDispatcher() = default;
 
+  void SetService(PrefetchService* service) override{};
+
   void AddCandidatePrefetchURLs(
-      const std::vector<PrefetchURL>& suggested_urls) override {
-    latest_prefetch_urls = suggested_urls;
+      const std::string& name_space,
+      const std::vector<PrefetchURL>& prefetch_urls) override {
+    latest_name_space = name_space;
+    latest_prefetch_urls = prefetch_urls;
     new_suggestions_count++;
   }
 
   void RemoveAllUnprocessedPrefetchURLs(
       const std::string& name_space) override {
-    DCHECK_EQ(name_space, kSuggestedArticlesNamespace);
+    DCHECK_EQ(kSuggestedArticlesNamespace, name_space);
     latest_prefetch_urls.clear();
     remove_all_suggestions_count++;
   }
 
-  void RemovePrefetchURLsByClientId(const ClientId& client_id) override {
-    DCHECK_EQ(client_id.name_space, kSuggestedArticlesNamespace);
+  void RemovePrefetchURLsByClientId(const std::string& name_space,
+                                    const std::string& client_id) override {
+    DCHECK_EQ(kSuggestedArticlesNamespace, name_space);
     remove_by_client_id_count++;
-    last_removed_client_id = base::MakeUnique<ClientId>(client_id);
+    last_removed_name_space = name_space;
+    last_removed_client_id = client_id;
   }
 
   void BeginBackgroundTask(
       std::unique_ptr<ScopedBackgroundTask> task) override {}
   void StopBackgroundTask(ScopedBackgroundTask* task) override {}
 
+  std::string latest_name_space;
   std::vector<PrefetchURL> latest_prefetch_urls;
-  std::unique_ptr<ClientId> last_removed_client_id;
+  std::string last_removed_name_space;
+  std::string last_removed_client_id;
 
   int new_suggestions_count = 0;
   int remove_all_suggestions_count = 0;
@@ -68,6 +76,10 @@ class TestingPrefetchService : public PrefetchService {
   TestingPrefetchService() = default;
 
   PrefetchDispatcher* GetDispatcher() override { return &dispatcher; };
+  PrefetchStore* GetStore() override {
+    CHECK(false);
+    return nullptr;
+  };
 
   TestingPrefetchDispatcher dispatcher;
 };
@@ -168,9 +180,8 @@ TEST_F(OfflinePageSuggestedArticlesObserverTest,
   EXPECT_EQ(1U, test_prefetch_dispatcher()->latest_prefetch_urls.size());
   EXPECT_EQ(test_url_1,
             test_prefetch_dispatcher()->latest_prefetch_urls[0].url);
-  EXPECT_EQ(
-      kSuggestedArticlesNamespace,
-      test_prefetch_dispatcher()->latest_prefetch_urls[0].client_id.name_space);
+  EXPECT_EQ(kSuggestedArticlesNamespace,
+            test_prefetch_dispatcher()->latest_name_space);
 }
 
 TEST_F(OfflinePageSuggestedArticlesObserverTest, RemovesAllOnBadStatus) {
@@ -208,8 +219,10 @@ TEST_F(OfflinePageSuggestedArticlesObserverTest, RemovesClientIdOnInvalidated) {
       ntp_snippets::ContentSuggestion::ID(category, test_url_1.spec()));
 
   EXPECT_EQ(1, test_prefetch_dispatcher()->remove_by_client_id_count);
-  EXPECT_EQ(ClientId(kSuggestedArticlesNamespace, test_url_1.spec()),
-            *test_prefetch_dispatcher()->last_removed_client_id);
+  EXPECT_EQ(test_url_1.spec(),
+            test_prefetch_dispatcher()->last_removed_client_id);
+  EXPECT_EQ(kSuggestedArticlesNamespace,
+            test_prefetch_dispatcher()->last_removed_name_space);
 }
 
 }  // namespace offline_pages