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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_REQUEST_SCHEDULER_H_
      6 #define CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_REQUEST_SCHEDULER_H_
      7 
      8 #include "base/bind.h"
      9 #include "base/gtest_prod_util.h"
     10 #include "base/time/time.h"
     11 #include "base/timer/timer.h"
     12 
     13 class PrefService;
     14 
     15 namespace chrome_variations {
     16 
     17 // A helper class that makes VariationsService requests at the correct times.
     18 class VariationsRequestScheduler {
     19  public:
     20   virtual ~VariationsRequestScheduler();
     21 
     22   // Starts the task on a schedule.
     23   virtual void Start();
     24 
     25   // Resets the scheduler if it is currently on a timer.
     26   virtual void Reset();
     27 
     28   // Schedules a fetch shortly, for example to re-try the initial request which
     29   // may have failed.
     30   void ScheduleFetchShortly();
     31 
     32   // Factory method for this class.
     33   static VariationsRequestScheduler* Create(const base::Closure& task,
     34                                             PrefService* local_state);
     35 
     36  protected:
     37   // |task| is the closure to call when the scheduler deems ready.
     38   explicit VariationsRequestScheduler(const base::Closure& task);
     39 
     40   // Getter for derived classes.
     41   base::Closure task() const;
     42 
     43  private:
     44   FRIEND_TEST_ALL_PREFIXES(VariationsRequestSchedulerTest,
     45                            ScheduleFetchShortly);
     46 
     47   // The task scheduled by this class.
     48   base::Closure task_;
     49 
     50   // The timer used to repeatedly ping the server. Keep this as an instance
     51   // member so if VariationsRequestScheduler goes out of scope, the timer is
     52   // automatically canceled.
     53   base::RepeatingTimer<VariationsRequestScheduler> timer_;
     54 
     55   // A one-shot timer used for scheduling out-of-band fetches.
     56   base::OneShotTimer<VariationsRequestScheduler> one_shot_timer_;
     57 
     58   DISALLOW_COPY_AND_ASSIGN(VariationsRequestScheduler);
     59 };
     60 
     61 }  // namespace chrome_variations
     62 
     63 #endif  // CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_REQUEST_SCHEDULER_H_
     64