[Sync] Add support for server controlled nudge delays

sync/engine/sync_scheduler_impl.h

 // Copyright 2012 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 SYNC_ENGINE_SYNC_SCHEDULER_IMPL_H_
 #define SYNC_ENGINE_SYNC_SCHEDULER_IMPL_H_
 
 #include <map>
 #include <string>
 
@@ skipping 38 matching lines @@
                     Syncer* syncer);
 
   // Calls Stop().
   virtual ~SyncSchedulerImpl();
 
   virtual void Start(Mode mode) OVERRIDE;
   virtual void ScheduleConfiguration(
       const ConfigurationParams& params) OVERRIDE;
   virtual void Stop() OVERRIDE;
   virtual void ScheduleLocalNudge(
-      const base::TimeDelta& desired_delay,
       ModelTypeSet types,
       const tracked_objects::Location& nudge_location) OVERRIDE;
   virtual void ScheduleLocalRefreshRequest(
-      const base::TimeDelta& desired_delay,
       ModelTypeSet types,
       const tracked_objects::Location& nudge_location) OVERRIDE;
   virtual void ScheduleInvalidationNudge(
-      const base::TimeDelta& desired_delay,
       syncer::ModelType type,
       scoped_ptr<InvalidationInterface> invalidation,
       const tracked_objects::Location& nudge_location) OVERRIDE;
   virtual void ScheduleInitialSyncNudge(syncer::ModelType model_type) OVERRIDE;
   virtual void SetNotificationsEnabled(bool notifications_enabled) OVERRIDE;
 
-  virtual base::TimeDelta GetSessionsCommitDelay() const OVERRIDE;
-
   virtual void OnCredentialsUpdated() OVERRIDE;
   virtual void OnConnectionStatusChange() OVERRIDE;
 
   // SyncSession::Delegate implementation.
   virtual void OnThrottled(const base::TimeDelta& throttle_duration) OVERRIDE;
   virtual void OnTypesThrottled(
       ModelTypeSet types,
       const base::TimeDelta& throttle_duration) OVERRIDE;
   virtual bool IsCurrentlyThrottled() OVERRIDE;
   virtual void OnReceivedShortPollIntervalUpdate(
       const base::TimeDelta& new_interval) OVERRIDE;
   virtual void OnReceivedLongPollIntervalUpdate(
       const base::TimeDelta& new_interval) OVERRIDE;
-  virtual void OnReceivedSessionsCommitDelay(
-      const base::TimeDelta& new_delay) OVERRIDE;
+  virtual void OnReceivedCustomNudgeDelays(
+      const std::map<ModelType, int>& nudge_delays) OVERRIDE;
   virtual void OnReceivedClientInvalidationHintBufferSize(int size) OVERRIDE;
   virtual void OnSyncProtocolError(
       const SyncProtocolError& sync_protocol_error) OVERRIDE;
   virtual void OnReceivedGuRetryDelay(const base::TimeDelta& delay) OVERRIDE;
   virtual void OnReceivedMigrationRequest(syncer::ModelTypeSet types) OVERRIDE;
 
   // Returns true if the client is currently in exponential backoff.
   bool IsBackingOff() const;
 
+  // Returns the nudge delay to be used based on |types|.
+  base::TimeDelta GetNudgeDelayForTypes(ModelTypeSet types) const;
+
  private:
   enum JobPriority {
     // Non-canary jobs respect exponential backoff.
     NORMAL_PRIORITY,
     // Canary jobs bypass exponential backoff, so use with extreme caution.
     CANARY_PRIORITY
   };
 
   enum PollAdjustType {
     // Restart the poll interval.
@@ skipping 33 matching lines @@
     WaitInterval(Mode mode, base::TimeDelta length);
 
     static const char* GetModeString(Mode mode);
 
     Mode mode;
     base::TimeDelta length;
   };
 
   static const char* GetModeString(Mode mode);
 
+  void SetDefaultNudgeDelay(int delay_ms);
+
   // Invoke the syncer to perform a nudge job.
   void DoNudgeSyncSessionJob(JobPriority priority);
 
   // Invoke the syncer to perform a configuration job.
   void DoConfigurationSyncSessionJob(JobPriority priority);
 
   // Helper function for Do{Nudge,Configuration}SyncSessionJob.
   void HandleFailure(
       const sessions::ModelNeutralState& model_neutral_state);
 
@@ skipping 81 matching lines @@
   const std::string name_;
 
   // Set in Start(), unset in Stop().
   bool started_;
 
   // Modifiable versions of kDefaultLongPollIntervalSeconds which can be
   // updated by the server.
   base::TimeDelta syncer_short_poll_interval_seconds_;
   base::TimeDelta syncer_long_poll_interval_seconds_;
 
-  // Server-tweakable sessions commit delay.
-  base::TimeDelta sessions_commit_delay_;
+  // Server-tweakable custom nudge delays.

[rlarocque, 2014/08/20 00:13:31]

The nudge delay tracking code is somewhat complicated, and reasonably
self-contained.  Maybe you could pull these member variables, and all the
functions that reference them, into a separate class?

SyncSchedulerImpl is already too big.  Let's not make it worse.

[Nicolas Zea, 2014/08/20 22:49:43]

Discussed offline, moved this state into NudgeTracker/DataTypeTracker.

+  int minimum_nudge_delay_ms_;
+  std::map<ModelType, base::TimeDelta> nudge_delays_;
 
   // Periodic timer for polling.  See AdjustPolling.
   base::RepeatingTimer<SyncSchedulerImpl> poll_timer_;
 
   // The mode of operation.
   Mode mode_;
 
   // Current wait state.  Null if we're not in backoff and not throttled.
   scoped_ptr<WaitInterval> wait_interval_;
 
@@ skipping 63 matching lines @@
   // A second factory specially for weak_handle_this_, to allow the handle
   // to be const and alleviate threading concerns.
   base::WeakPtrFactory<SyncSchedulerImpl> weak_ptr_factory_for_weak_handle_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncSchedulerImpl);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_ENGINE_SYNC_SCHEDULER_IMPL_H_