Add InvalidationStateTracker::Forget() to erase an entry from storage.

sync/notifier/registration_manager.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/registration_manager.h"
 
 #include <algorithm>
 #include <cstddef>
 #include <iterator>
 #include <string>
@@ skipping 48 matching lines @@
     invalidation::InvalidationClient* invalidation_client)
     : invalidation_client_(invalidation_client) {
   DCHECK(invalidation_client_);
 }
 
 RegistrationManager::~RegistrationManager() {
   DCHECK(CalledOnValidThread());
   STLDeleteValues(&registration_statuses_);
 }
 
-void RegistrationManager::UpdateRegisteredIds(const ObjectIdSet& ids) {
+ObjectIdSet RegistrationManager::UpdateRegisteredIds(const ObjectIdSet& ids) {
   DCHECK(CalledOnValidThread());
 
   const ObjectIdSet& old_ids = GetRegisteredIds();
   const ObjectIdSet& to_register = ids;
   ObjectIdSet to_unregister;
   std::set_difference(old_ids.begin(), old_ids.end(),
                       ids.begin(), ids.end(),
                       std::inserter(to_unregister, to_unregister.begin()),
                       ObjectIdLessThan());
 
   for (ObjectIdSet::const_iterator it = to_unregister.begin();
        it != to_unregister.end(); ++it) {
     UnregisterId(*it);
   }
 
   for (ObjectIdSet::const_iterator it = to_register.begin();
        it != to_register.end(); ++it) {
     if (!ContainsKey(registration_statuses_, *it)) {
       registration_statuses_.insert(
           std::make_pair(*it, new RegistrationStatus(*it, this)));
     }
     if (!IsIdRegistered(*it)) {
       TryRegisterId(*it, false /* is-retry */);
     }
   }
+
+  return to_unregister;
 }
 
 void RegistrationManager::MarkRegistrationLost(
     const invalidation::ObjectId& id) {
   DCHECK(CalledOnValidThread());
   RegistrationStatusMap::const_iterator it = registration_statuses_.find(id);
   if (it == registration_statuses_.end()) {
     DLOG(WARNING) << "Attempt to mark non-existent registration for "
                   << ObjectIdToString(id) << " as lost";
     return;
@@ skipping 189 matching lines @@
 bool RegistrationManager::IsIdRegistered(
     const invalidation::ObjectId& id) const {
   DCHECK(CalledOnValidThread());
   RegistrationStatusMap::const_iterator it =
       registration_statuses_.find(id);
   return it != registration_statuses_.end() &&
       it->second->state == invalidation::InvalidationListener::REGISTERED;
 }
 
 }  // namespace syncer