Implement Invalidator::Acknowledge

sync/notifier/ack_tracker.cc

 // Copyright (c) 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.
 
 #include "sync/notifier/ack_tracker.h"
 
 #include <algorithm>
 #include <iterator>
 #include <utility>
 
@@ skipping 77 matching lines @@
 
 void AckTracker::Clear() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   timer_.Stop();
   STLDeleteValues(&queue_);
 }
 
 void AckTracker::Track(const ObjectIdSet& ids) {
   DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(!ids.empty());
 
   scoped_ptr<Entry> entry(new Entry(
       create_backoff_entry_callback_.Run(&kDefaultBackoffPolicy), ids));
   // This is a small hack. When net::BackoffRequest is first created,
   // GetReleaseTime() always returns the default base::TimeTicks value: 0.
   // In order to work around that, we mark it as failed right away.
   entry->backoff->InformOfRequest(false /* succeeded */);
   const base::TimeTicks release_time = entry->backoff->GetReleaseTime();
   queue_.insert(std::make_pair(release_time, entry.release()));
   NudgeTimer();
@@ skipping 108 matching lines @@
   return queue_.empty();
 }
 
 const base::Timer& AckTracker::GetTimerForTest() const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   return timer_;
 }
 
 }  // namespace syncer