[NTP::SectionOrder] Add a flag to choose category ranker.

chrome/browser/ntp_snippets/content_suggestions_service_factory.cc

 // Copyright 2016 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 "chrome/browser/ntp_snippets/content_suggestions_service_factory.h"
 
 #include <utility>
 
 #include "base/feature_list.h"
 #include "base/files/file_path.h"
@@ skipping 11 matching lines @@
 #include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_features.h"
 #include "components/bookmarks/browser/bookmark_model.h"
 #include "components/browser_sync/profile_sync_service.h"
 #include "components/image_fetcher/image_decoder.h"
 #include "components/image_fetcher/image_fetcher.h"
 #include "components/image_fetcher/image_fetcher_impl.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "components/keyed_service/core/service_access_type.h"
 #include "components/ntp_snippets/bookmarks/bookmark_suggestions_provider.h"
+#include "components/ntp_snippets/category_rankers/category_ranker.h"
+#include "components/ntp_snippets/category_rankers/click_based_category_ranker.h"
 #include "components/ntp_snippets/category_rankers/constant_category_ranker.h"
 #include "components/ntp_snippets/content_suggestions_service.h"
 #include "components/ntp_snippets/features.h"
 #include "components/ntp_snippets/ntp_snippets_constants.h"
 #include "components/ntp_snippets/remote/ntp_snippets_fetcher.h"
 #include "components/ntp_snippets/remote/ntp_snippets_scheduler.h"
 #include "components/ntp_snippets/remote/remote_suggestions_database.h"
 #include "components/ntp_snippets/remote/remote_suggestions_provider.h"
 #include "components/ntp_snippets/remote/remote_suggestions_status_service.h"
 #include "components/ntp_snippets/sessions/foreign_sessions_suggestions_provider.h"
 #include "components/ntp_snippets/sessions/tab_delegate_sync_adapter.h"
 #include "components/prefs/pref_service.h"
 #include "components/safe_json/safe_json_parser.h"
 #include "components/signin/core/browser/profile_oauth2_token_service.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "components/translate/core/browser/language_model.h"
+#include "components/variations/variations_associated_data.h"
 #include "components/version_info/version_info.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/storage_partition.h"
 #include "google_apis/google_api_keys.h"
 #include "net/url_request/url_request_context_getter.h"
 
 #if defined(OS_ANDROID)
 #include "chrome/browser/android/chrome_feature_list.h"
 #include "chrome/browser/android/ntp/ntp_snippets_launcher.h"
@@ skipping 10 matching lines @@
 using offline_pages::OfflinePageModel;
 using offline_pages::OfflinePageModelFactory;
 using physical_web::PhysicalWebDataSource;
 #endif  // OS_ANDROID
 
 using bookmarks::BookmarkModel;
 using content::BrowserThread;
 using history::HistoryService;
 using image_fetcher::ImageFetcherImpl;
 using ntp_snippets::BookmarkSuggestionsProvider;
+using ntp_snippets::CategoryRanker;
+using ntp_snippets::ClickBasedCategoryRanker;
+using ntp_snippets::ConstantCategoryRanker;
 using ntp_snippets::ContentSuggestionsService;
 using ntp_snippets::ForeignSessionsSuggestionsProvider;
 using ntp_snippets::NTPSnippetsFetcher;
 using ntp_snippets::NTPSnippetsScheduler;
 using ntp_snippets::RemoteSuggestionsDatabase;
 using ntp_snippets::RemoteSuggestionsProvider;
 using ntp_snippets::RemoteSuggestionsStatusService;
 using ntp_snippets::TabDelegateSyncAdapter;
 using suggestions::ImageDecoderImpl;
 using syncer::SyncService;
@@ skipping 94 matching lines @@
 void RegisterForeignSessionsProvider(SyncService* sync_service,
                                      ContentSuggestionsService* service,
                                      PrefService* pref_service) {
   std::unique_ptr<TabDelegateSyncAdapter> sync_adapter =
       base::MakeUnique<TabDelegateSyncAdapter>(sync_service);
   auto provider = base::MakeUnique<ForeignSessionsSuggestionsProvider>(
       service, std::move(sync_adapter), pref_service);
   service->RegisterProvider(std::move(provider));
 }
 
+std::unique_ptr<CategoryRanker> BuildCategoryRanker(PrefService* pref_service) {
+  std::string category_ranker_parameter = variations::GetVariationParamValue(
+      ntp_snippets::kStudyName, "category_ranker");
+
+  if (category_ranker_parameter.empty()) {
+    // Default, Enabled or Disabled.
+    return base::MakeUnique<ConstantCategoryRanker>();
+  }
+  if (category_ranker_parameter == "constant") {
+    return base::MakeUnique<ConstantCategoryRanker>();
+  }
+  if (category_ranker_parameter == "click_based") {
+    return base::MakeUnique<ClickBasedCategoryRanker>(pref_service);
+  }
+
+  NOTREACHED() << "The category_ranker parameter value is "
+               << category_ranker_parameter;
+  return nullptr;
+}
+
 }  // namespace
 
 // static
 ContentSuggestionsServiceFactory*
 ContentSuggestionsServiceFactory::GetInstance() {
   return base::Singleton<ContentSuggestionsServiceFactory>::get();
 }
 
 // static
 ContentSuggestionsService* ContentSuggestionsServiceFactory::GetForProfile(
@@ skipping 34 matching lines @@
   // Create the ContentSuggestionsService.
   State state =
       base::FeatureList::IsEnabled(ntp_snippets::kContentSuggestionsFeature)
           ? State::ENABLED
           : State::DISABLED;
   SigninManagerBase* signin_manager =
       SigninManagerFactory::GetForProfile(profile);
   HistoryService* history_service = HistoryServiceFactory::GetForProfile(
       profile, ServiceAccessType::EXPLICIT_ACCESS);
   PrefService* pref_service = profile->GetPrefs();
-  auto category_ranker =
-      base::MakeUnique<ntp_snippets::ConstantCategoryRanker>();
+  std::unique_ptr<CategoryRanker> category_ranker =
+      BuildCategoryRanker(pref_service);
   auto* service =
       new ContentSuggestionsService(state, signin_manager, history_service,
                                     pref_service, std::move(category_ranker));
   if (state == State::DISABLED) {
     // Since we won't initialise the services, they won't get a chance to
     // unschedule their tasks. We do it explicitly here instead.
     ClearScheduledTasks();
     return service;
   }
 
@@ skipping 51 matching lines @@
                             language_model, pref_service, profile);
   }
 
   if (base::FeatureList::IsEnabled(
           ntp_snippets::kForeignSessionsSuggestionsFeature)) {
     RegisterForeignSessionsProvider(sync_service, service, pref_service);
   }
 
   return service;
 }