[Sync] Add support for server controlled nudge delays

sync/sessions/data_type_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.
 
 #ifndef SYNC_SESSIONS_DATA_TYPE_TRACKER_H_
 #define SYNC_SESSIONS_DATA_TYPE_TRACKER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 13 matching lines @@
 // A class to track the per-type scheduling data.
 class DataTypeTracker {
  public:
   explicit DataTypeTracker();
   ~DataTypeTracker();
 
   // For STL compatibility, we do not forbid the creation of a default copy
   // constructor and assignment operator.
 
   // Tracks that a local change has been made to this type.
-  void RecordLocalChange();
+  // Returns the current local change nudge delay for this type.
+  base::TimeDelta RecordLocalChange();
 
   // Tracks that a local refresh request has been made for this type.
   void RecordLocalRefreshRequest();
 
   // Tracks that we received invalidation notifications for this type.
   void RecordRemoteInvalidation(scoped_ptr<InvalidationInterface> incoming);
 
   // Takes note that initial sync is pending for this type.
   void RecordInitialSyncRequired();
 
@@ skipping 44 matching lines @@
   // be called unless IsThrottled() returns true.  The returned value will be
   // increased to zero if it would otherwise have been negative.
   base::TimeDelta GetTimeUntilUnthrottle(base::TimeTicks now) const;
 
   // Throttles the type from |now| until |now| + |duration|.
   void ThrottleType(base::TimeDelta duration, base::TimeTicks now);
 
   // Unthrottles the type if |now| >= the throttle expiry time.
   void UpdateThrottleState(base::TimeTicks now);
 
+  // Update the local change nudge delay for this type.
+  void UpdateLocalNudgeDelay(base::TimeDelta delay);
+
  private:
   // Number of local change nudges received for this type since the last
   // successful sync cycle.
   int local_nudge_count_;
 
   // Number of local refresh requests received for this type since the last
   // successful sync cycle.
   int local_refresh_request_count_;
 
   // The list of invalidations received since the last successful sync cycle.
   // This list may be incomplete.  See also:
   // drop_tracker_.IsRecoveringFromDropEvent() and server_payload_overflow_.
   //
   // This list takes ownership of its contents.
   ScopedVector<InvalidationInterface> pending_invalidations_;
 
   size_t payload_buffer_size_;
 
   // Set to true if this type is ready for, but has not yet completed initial
   // sync.
   bool initial_sync_required_;
 
   // If !unthrottle_time_.is_null(), this type is throttled and may not download
   // or commit data until the specified time.
   base::TimeTicks unthrottle_time_;
 
   // A helper to keep track invalidations we dropped due to overflow.
   scoped_ptr<InvalidationInterface> last_dropped_invalidation_;
 
+  // The amount of time to delay a sync cycle by when a local change for this
+  // type occurs.
+  base::TimeDelta nudge_delay_;
+
   DISALLOW_COPY_AND_ASSIGN(DataTypeTracker);
 };
 
 }  // namespace sessions
 }  // namespace syncer
 
 #endif  // SYNC_SESSIONS_DATA_TYPE_TRACKER_H_