Let SyncManagerFactory create different types of sync managers according to

sync/internal_api/sync_manager_factory.cc

Index: sync/internal_api/sync_manager_factory.cc
diff --git a/sync/internal_api/sync_manager_factory.cc b/sync/internal_api/sync_manager_factory.cc
index 9d784b46ada76cb50d03ace2cf040cdd00a14f2e..c3f09d32e5b09f3e7eb1cffd3511d804339636d4 100644
--- a/sync/internal_api/sync_manager_factory.cc
+++ b/sync/internal_api/sync_manager_factory.cc
@@ -4,11 +4,14 @@
 
 #include "sync/internal_api/public/sync_manager_factory.h"
 
+#include "sync/internal_api/sync_backup_manager.h"
 #include "sync/internal_api/sync_manager_impl.h"
+#include "sync/internal_api/sync_rollback_manager.h"
 
 namespace syncer {
 
-SyncManagerFactory::SyncManagerFactory() {
+SyncManagerFactory::SyncManagerFactory(SyncManagerFactory::MANAGER_TYPE type)
+    : type_(type) {
 }
 
 SyncManagerFactory::~SyncManagerFactory() {
@@ -16,7 +19,17 @@ SyncManagerFactory::~SyncManagerFactory() {
 
 scoped_ptr<SyncManager> SyncManagerFactory::CreateSyncManager(
       const std::string name) {
-  return scoped_ptr<SyncManager>(new SyncManagerImpl(name));
+  switch (type_) {
+    case NORMAL:
+      return scoped_ptr<SyncManager>(new SyncManagerImpl(name));
+    case BACKUP:
+      return scoped_ptr<SyncManager>(new SyncBackupManager());
+    case ROLLBACK:
+      return scoped_ptr<SyncManager>(new SyncRollbackManager());
+    default:
+      NOTREACHED();
+      return scoped_ptr<SyncManager>(new SyncManagerImpl(name));
+  }
 }
 
 }  // namespace syncer