[Background fetching] Background fetching when opening an NTP.

components/ntp_snippets/remote/scheduling_remote_suggestions_provider.h

 // 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.
 
 #ifndef COMPONENTS_NTP_SNIPPETS_REMOTE_SCHEDULING_REMOTE_SUGGESTIONS_PROVIDER_H_
 #define COMPONENTS_NTP_SNIPPETS_REMOTE_SCHEDULING_REMOTE_SUGGESTIONS_PROVIDER_H_
 
 #include <memory>
 #include <set>
 #include <string>
@@ skipping 96 matching lines @@
   // After the call, updates will be scheduled in the future. Idempotent, can be
   // run any time later without impacting the current schedule.
   // If you want to enforce rescheduling, call Unschedule() and then Schedule().
   void StartScheduling();
 
   // After the call, no updates will happen before another call to Schedule().
   // Idempotent, can be run any time later without impacting the current
   // schedule.
   void StopScheduling();
 
+  // Checks whether it is time to perform a soft background fetch, according to
+  // |schedule|.
+  bool ShouldRefetchInTheBackgroundNow();
+
   // Callback after Fetch is completed.
   void FetchFinished(const FetchDoneCallback& callback,
-                     Status status_code,
+                     Status fetch_status,
                      std::vector<ContentSuggestion> suggestions);
 
+  // Callback after RefetchInTheBackground is completed.
+  void RefetchInTheBackgroundFinished(
+      std::unique_ptr<FetchStatusCallback> callback,
+      Status fetch_status);
+
   FetchingSchedule GetDesiredFetchingSchedule() const;
   FetchingSchedule GetLastFetchingSchedule() const;
   void StoreLastFetchingSchedule(const FetchingSchedule& schedule);
 
-  // Common function to call after each fetch.
-  void OnFetchCompleted(Status status);
-
   // Applies the provided |schedule|.
-  void ApplyFetchingSchedule(const FetchingSchedule& schedule);
+  void ApplyFetchingSchedule(const FetchingSchedule& schedule,
+                             bool also_apply_persistent_schedule);
 
   // Interface for doing all the actual work (apart from scheduling).
   std::unique_ptr<RemoteSuggestionsProvider> provider_;
 
   // Interface for scheduling hard fetches, OS dependent. Not owned, may be
   // null.
   PersistentScheduler* persistent_scheduler_;
 
+  bool background_fetch_in_progress_;
+
   // Used to adapt the schedule based on usage activity of the user. Not owned.
   const UserClassifier* user_classifier_;
 
   PrefService* pref_service_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulingRemoteSuggestionsProvider);
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_REMOTE_SCHEDULING_REMOTE_SUGGESTIONS_PROVIDER_H_