Snippets are enabled when search suggestions are enabled.

components/ntp_snippets/ntp_snippets_service.h

 // 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.
 
 #ifndef COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_
 #define COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 46 matching lines @@
                            public sync_driver::SyncServiceObserver {
  public:
   using ImageFetchedCallback =
       base::Callback<void(const std::string& snippet_id, const gfx::Image&)>;
 
   // |application_language_code| should be a ISO 639-1 compliant string, e.g.
   // 'en' or 'en-US'. Note that this code should only specify the language, not
   // the locale, so 'en_US' (English language with US locale) and 'en-GB_US'
   // (British English person in the US) are not language codes.
   NTPSnippetsService(
+      bool enabled,
       PrefService* pref_service,
       sync_driver::SyncService* sync_service,
       suggestions::SuggestionsService* suggestions_service,
       scoped_refptr<base::SequencedTaskRunner> file_task_runner,
       const std::string& application_language_code,
       NTPSnippetsScheduler* scheduler,
       std::unique_ptr<NTPSnippetsFetcher> snippets_fetcher,
       std::unique_ptr<image_fetcher::ImageFetcher> image_fetcher);
   ~NTPSnippetsService() override;
 
   static void RegisterProfilePrefs(PrefRegistrySimple* registry);
 
-  void Init(bool enabled);
-
   // Inherited from KeyedService.
   void Shutdown() override;
 
   // Fetches snippets from the server and adds them to the current ones.
   void FetchSnippets();
   // Fetches snippets from the server for specified hosts (overriding
   // suggestions from the suggestion service) and adds them to the current ones.
   void FetchSnippetsFromHosts(const std::set<std::string>& hosts);
 
   // Available snippets.
@@ skipping 64 matching lines @@
   void StoreSnippetHostsToPrefs(const std::set<std::string>& hosts);
 
   void LoadingSnippetsFinished();
 
   // Checks whether the state of the sync service is incompatible with showing
   // snippets. We need history sync to be active.
   // Note: The state is considered compatible if the service is still
   // initializing and the sync state is not known.
   bool IsSyncStateIncompatible();
 
-  enum class State {

[dgn, 2016/05/24 16:38:35]

treib@ is adding a LOADED state, and I'm adding a DISABLED one. I don't think
this should be removed.

[Marc Treib, 2016/05/24 16:55:24]

+1 :)

[Michael van Ouwerkerk, 2016/05/24 16:58:09]

Done.

-    NOT_INITED,
-    INITED,
-    SHUT_DOWN
-  } state_;
+  // Whether Shutdown has been called.
+  bool shutdown_;
 
+  // When |enabled_| is true the service will fetch snippets from the server
+  // using |snippets_fetcher_|, load snippets from device storage, and schedule
+  // the |scheduler_|.
   bool enabled_;
 
   PrefService* pref_service_;
 
   sync_driver::SyncService* sync_service_;
 
   // The observer for the SyncService. When the sync state changes,
   // SyncService will call |OnStateChanged|, which is propagated to the
   // snippet observers.
   ScopedObserver<sync_driver::SyncService, sync_driver::SyncServiceObserver>
@@ skipping 48 matching lines @@
   // or because a requirement (e.g. History Sync) is not fulfilled anymore.
   virtual void NTPSnippetsServiceDisabled() = 0;
 
  protected:
   virtual ~NTPSnippetsServiceObserver() {}
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_