[Sync] Replacing NULL with nullptr in code and null in comments for components/sync/

components/sync/driver/glue/sync_backend_host_mock.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 "components/sync/driver/glue/sync_backend_host_mock.h"
 
 #include "components/sync/driver/sync_frontend.h"
 #include "components/sync/engine/activation_context.h"
 
 namespace syncer {
@@ skipping 63 matching lines @@
     ChangeProcessor* change_processor) {}
 void SyncBackendHostMock::DeactivateDirectoryDataType(ModelType type) {}
 
 void SyncBackendHostMock::ActivateNonBlockingDataType(
     ModelType type,
     std::unique_ptr<ActivationContext> activation_context) {}
 
 void SyncBackendHostMock::DeactivateNonBlockingDataType(ModelType type) {}
 
 UserShare* SyncBackendHostMock::GetUserShare() const {
-  return NULL;
+  return nullptr;
 }
 
 SyncBackendHost::Status SyncBackendHostMock::GetDetailedStatus() {
   return SyncBackendHost::Status();
 }
 
 SyncCycleSnapshot SyncBackendHostMock::GetLastCycleSnapshot() const {
   return SyncCycleSnapshot();
 }
 
@@ skipping 17 matching lines @@
     const BaseTransaction* trans) const {
   return false;
 }
 
 void SyncBackendHostMock::GetModelSafeRoutingInfo(
     ModelSafeRoutingInfo* out) const {}
 
 void SyncBackendHostMock::FlushDirectory() const {}
 
 base::MessageLoop* SyncBackendHostMock::GetSyncLoopForTesting() {
-  return NULL;
+  return nullptr;
 }
 
 void SyncBackendHostMock::RefreshTypesForTest(ModelTypeSet types) {}
 
 void SyncBackendHostMock::RequestBufferedProtocolEventsAndEnableForwarding() {}
 
 void SyncBackendHostMock::DisableProtocolEventForwarding() {}
 
 void SyncBackendHostMock::EnableDirectoryTypeDebugInfoForwarding() {}
 
 void SyncBackendHostMock::DisableDirectoryTypeDebugInfoForwarding() {}
 
 void SyncBackendHostMock::set_fail_initial_download(bool should_fail) {
   fail_initial_download_ = should_fail;
 }
 
 void SyncBackendHostMock::ClearServerData(
     const SyncManager::ClearServerDataCallback& callback) {
   callback.Run();
 }
 
 void SyncBackendHostMock::OnCookieJarChanged(bool account_mismatch,
                                              bool empty_jar) {}
 
 }  // namespace syncer