[Sync] Add support for server controlled nudge delays

sync/sessions/data_type_tracker.cc

 // 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.
 
 #include "sync/sessions/data_type_tracker.h"
 
 #include "base/logging.h"
 #include "sync/internal_api/public/base/invalidation_interface.h"
 #include "sync/sessions/nudge_tracker.h"
 
 namespace syncer {
 namespace sessions {
 
 DataTypeTracker::DataTypeTracker()
     : local_nudge_count_(0),
       local_refresh_request_count_(0),
       payload_buffer_size_(NudgeTracker::kDefaultMaxPayloadsPerType),
       initial_sync_required_(false) {
 }
 
 DataTypeTracker::~DataTypeTracker() { }
 
-void DataTypeTracker::RecordLocalChange() {
+base::TimeDelta DataTypeTracker::RecordLocalChange() {
   local_nudge_count_++;
+  return nudge_delay_;
 }
 
 void DataTypeTracker::RecordLocalRefreshRequest() {
   local_refresh_request_count_++;
 }
 
 void DataTypeTracker::RecordRemoteInvalidation(
     scoped_ptr<InvalidationInterface> incoming) {
   DCHECK(incoming);
 
@@ skipping 176 matching lines @@
                                       base::TimeTicks now) {
   unthrottle_time_ = std::max(unthrottle_time_, now + duration);
 }
 
 void DataTypeTracker::UpdateThrottleState(base::TimeTicks now) {
   if (now >= unthrottle_time_) {
     unthrottle_time_ = base::TimeTicks();
   }
 }
 
+void DataTypeTracker::UpdateLocalNudgeDelay(base::TimeDelta delay) {
+  nudge_delay_ = delay;
+}
+
 }  // namespace sessions
 }  // namespace syncer