[Sync] Split UserEventService into interface and impl, add fake impl, add unit tests.

chrome/browser/sync/user_event_service_factory.cc

 // Copyright 2017 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 "chrome/browser/sync/user_event_service_factory.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "chrome/common/channel_info.h"
 #include "components/browser_sync/profile_sync_service.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/base/report_unrecoverable_error.h"
-#include "components/sync/user_events/user_event_service.h"
+#include "components/sync/user_events/user_event_service_impl.h"
 #include "components/sync/user_events/user_event_sync_bridge.h"
 
 namespace browser_sync {
 
 // static
 UserEventServiceFactory* UserEventServiceFactory::GetInstance() {
   return base::Singleton<UserEventServiceFactory>::get();
 }
 
 // static
@@ skipping 15 matching lines @@
   Profile* profile = Profile::FromBrowserContext(context);
   syncer::ModelTypeStoreFactory store_factory =
       browser_sync::ProfileSyncService::GetModelTypeStoreFactory(
           syncer::USER_EVENTS, profile->GetPath());
   syncer::ModelTypeSyncBridge::ChangeProcessorFactory processor_factory =
       base::BindRepeating(&syncer::ModelTypeChangeProcessor::Create,
                           base::BindRepeating(&syncer::ReportUnrecoverableError,
                                               chrome::GetChannel()));
   auto bridge = base::MakeUnique<syncer::UserEventSyncBridge>(
       std::move(store_factory), std::move(processor_factory));
-  return new syncer::UserEventService(
+  return new syncer::UserEventServiceImpl(
       ProfileSyncServiceFactory::GetForProfile(profile), std::move(bridge));
 }
 
 }  // namespace browser_sync