[Sync] Add support for server controlled nudge delays

sync/sessions/nudge_tracker.h

 // Copyright 2013 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.
 //
 // A class to track the outstanding work required to bring the client back into
 // sync with the server.
 #ifndef SYNC_SESSIONS_NUDGE_TRACKER_H_
 #define SYNC_SESSIONS_NUDGE_TRACKER_H_
 
 #include <list>
 #include <map>
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base/invalidation_interface.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/protocol/sync.pb.h"
 #include "sync/sessions/data_type_tracker.h"
 
 namespace syncer {
 
 class ObjectIdInvalidationMap;
 
@@ skipping 21 matching lines @@
   // by SetSyncCycleStartTime(), SetNextRetryTime(), and
   // RecordSuccessfulSyncCycle().  Please refer to those functions for more
   // information on how this flag is maintained.
   bool IsRetryRequired() const;
 
   // Tells this class that all required update fetching or committing has
   // completed successfully.
   void RecordSuccessfulSyncCycle();
 
   // Takes note of a local change.
-  void RecordLocalChange(ModelTypeSet types);
+  // Returns the shortest nudge delay from the tracker of each type in |types|.
+  base::TimeDelta RecordLocalChange(ModelTypeSet types);
 
   // Takes note of a locally issued request to refresh a data type.
-  void RecordLocalRefreshRequest(ModelTypeSet types);
+  // Returns the current nudge delay for a local refresh.
+  base::TimeDelta RecordLocalRefreshRequest(ModelTypeSet types);
 
   // Takes note of the receipt of an invalidation notice from the server.
-  void RecordRemoteInvalidation(syncer::ModelType type,
-                                scoped_ptr<InvalidationInterface> invalidation);
+  // Returns the current nudge delay for a remote invalidation.
+  base::TimeDelta RecordRemoteInvalidation(
+      syncer::ModelType type,
+      scoped_ptr<InvalidationInterface> invalidation);
 
   // Take note that an initial sync is pending for this type.
   void RecordInitialSyncRequired(syncer::ModelType type);
 
   // These functions should be called to keep this class informed of the status
   // of the connection to the invalidations server.
   void OnInvalidationsEnabled();
   void OnInvalidationsDisabled();
 
   // Marks |types| as being throttled from |now| until |now| + |length|.
@@ skipping 60 matching lines @@
   //
   // This is a request sent to us as part of a server response requesting
   // that the client perform a GetUpdate request at |next_retry_time| to
   // fetch any updates it may have missed in the first attempt.
   //
   // To avoid strange results from IsRetryRequired() during a sync cycle, the
   // effects of this change are not guaranteed to take effect until
   // SetSyncCycleStartTime() is called at the start of the *next* sync cycle.
   void SetNextRetryTime(base::TimeTicks next_retry_time);
 
+  // Update the per-datatype local change nudge delays.
+  void OnReceivedCustomNudgeDelays(
+      const std::map<ModelType, base::TimeDelta>& delay_map);
+
+  // Update the default nudge delay.
+  void SetDefaultNudgeDelay(base::TimeDelta nudge_delay);
+
  private:
   typedef std::map<ModelType, DataTypeTracker*> TypeTrackerMap;
 
   TypeTrackerMap type_trackers_;
   STLValueDeleter<TypeTrackerMap> type_tracker_deleter_;
 
   // Merged updates source.  This should be obsolete, but the server still
   // relies on it for some heuristics.
   sync_pb::GetUpdatesCallerInfo::GetUpdatesSource updates_source_;
 
@@ skipping 25 matching lines @@
 
   // The currently active retry GU time.  Will be null if there is no retry GU
   // pending at this time.
   base::TimeTicks current_retry_time_;
 
   // The time when the sync cycle started.  This value is maintained by
   // SetSyncCycleStartTime().  This may contain a stale value if we're not
   // currently in a sync cycle.
   base::TimeTicks sync_cycle_start_time_;
 
+  // Nudge delays for various events.
+  base::TimeDelta minimum_local_nudge_delay_;
+  base::TimeDelta local_refresh_nudge_delay_;
+  base::TimeDelta remote_invalidation_nudge_delay_;
+
   DISALLOW_COPY_AND_ASSIGN(NudgeTracker);
 };
 
 }  // namespace sessions
 }  // namespace syncer
 
 #endif  // SYNC_SESSIONS_NUDGE_TRACKER_H_