[Sync] Maintain a global_id mapping to update UserEvents that references navigations

components/sync/driver/fake_sync_service.cc

 // Copyright 2015 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/fake_sync_service.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/values.h"
 #include "components/sync/driver/data_type_controller.h"
 #include "components/sync/syncable/base_transaction.h"
@@ skipping 192 matching lines @@
   return base::WeakPtr<JsController>();
 }
 
 void FakeSyncService::GetAllNodes(
     const base::Callback<void(std::unique_ptr<base::ListValue>)>& callback) {}
 
 SigninManagerBase* FakeSyncService::signin() const {
   return nullptr;
 }
 
+GlobalIdMapper* FakeSyncService::GetGlobalIdMapper() const {
+  return nullptr;
+}
+
 bool FakeSyncService::IsPassphraseRequired() const {
   return false;
 }
 
 ModelTypeSet FakeSyncService::GetEncryptedDataTypes() const {
   return ModelTypeSet();
 }
 
 void FakeSyncService::Shutdown() {}
 
 }  // namespace syncer