[Offline Pages] Set up the initial prefetching service.

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 43 matching lines @@
 #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"
 #include "chrome/browser/android/offline_pages/offline_page_model_factory.h"
+#include "chrome/browser/android/offline_pages/offline_page_suggestions_observer.h"
 #include "chrome/browser/android/offline_pages/request_coordinator_factory.h"
 #include "chrome/browser/download/download_history.h"
 #include "chrome/browser/download/download_service.h"
 #include "chrome/browser/download/download_service_factory.h"
 #include "chrome/browser/ntp_snippets/download_suggestions_provider.h"
 #include "components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.h"
 #include "components/ntp_snippets/physical_web_pages/physical_web_page_suggestions_provider.h"
 #include "components/offline_pages/core/background/request_coordinator.h"
 #include "components/offline_pages/core/offline_page_feature.h"
 #include "components/offline_pages/core/offline_page_model.h"
@@ skipping 281 matching lines @@
   bool show_offline_page_downloads =
       !IsChromeHomeEnabled() &&
       base::FeatureList::IsEnabled(
           features::kOfflinePageDownloadSuggestionsFeature);
   if (show_asset_downloads || show_offline_page_downloads) {
     RegisterDownloadsProvider(
         show_offline_page_downloads ? offline_page_model : nullptr,
         show_asset_downloads ? download_manager : nullptr, download_history,
         service, pref_service);
   }
+
+  if (offline_pages::IsPrefetchingOfflinePagesEnabled()) {
+    offline_pages::OfflinePageSuggestionsObserver::
+        ObserveContentSuggestionsService(profile, offline_page_model, service);

[carlosk, 2017/04/11 17:31:36]

How about renaming the Observer* method to MaybeObserve* and moving the feature
check inside it? I think the logic deciding if an observer should observe or not
should be closer to the observer (and not the observed).

[dewittj, 2017/04/11 21:25:48]

Done, though I don't think the Maybe is strictly necessary.  PTAL.

+  }
+
 #endif  // OS_ANDROID
 
   // |bookmark_model| can be null in tests.
   if (base::FeatureList::IsEnabled(ntp_snippets::kBookmarkSuggestionsFeature) &&
       bookmark_model && !IsChromeHomeEnabled()) {
     RegisterBookmarkProvider(bookmark_model, service, pref_service);
   }
 
 #if defined(OS_ANDROID)
   if (IsPhysicalWebPageProviderEnabled()) {
@@ skipping 12 matching lines @@
           ntp_snippets::kForeignSessionsSuggestionsFeature)) {
     RegisterForeignSessionsProvider(sync_service, service, pref_service);
   }
 
   return service;
 
 #else
   return nullptr;
 #endif  // CONTENT_SUGGESTIONS_ENABLED
 }