Set up a backup schedule request if we have deferred requests.

components/offline_pages/background/scheduler.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_OFFLINE_PAGES_BACKGROUND_SCHEDULER_H_
 #define COMPONENTS_OFFLINE_PAGES_BACKGROUND_SCHEDULER_H_
 
 namespace offline_pages {
 
 // Interface of a class responsible for scheduling a task to initiate
@@ skipping 12 matching lines @@
     bool require_unmetered_network;
   };
 
   Scheduler() {}
   virtual ~Scheduler() {}
 
   // Schedules the triggering of a task subject to |trigger_conditions|.
   // This may overwrite any previous scheduled task with a new one for
   // these conditions. That is, only one set of triggering conditions
   // is scheduled at a time.
-  virtual void Schedule(const TriggerConditions& trigger_condition) = 0;
+  virtual void Schedule(const TriggerConditions& trigger_conditions) = 0;
+
+  // Schedules the triggering of a task in case Chromium is killed,
+  // so we can continue processing background download requests.  This will
+  // not overwrite existing tasks.
+  virtual void BackupSchedule(const TriggerConditions& trigger_conditions,
+                              long delay_in_seconds) = 0;
 
   // Unschedules the currently scheduled task, if any.
   virtual void Unschedule() = 0;
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_SCHEDULER_H_