Let SyncBackupManager keep backup data in memory until shutdown. Only persist

sync/internal_api/sync_rollback_manager_base_unittest.cc

Index: sync/internal_api/sync_rollback_manager_base_unittest.cc
diff --git a/sync/internal_api/sync_rollback_manager_base_unittest.cc b/sync/internal_api/sync_rollback_manager_base_unittest.cc
index a0866ea8f73e7e849f04bfcfddd1d6064d841e51..95662f649c078439b20350a6868b665250f3133e 100644
--- a/sync/internal_api/sync_rollback_manager_base_unittest.cc
+++ b/sync/internal_api/sync_rollback_manager_base_unittest.cc
@@ -25,6 +25,7 @@ class SyncTestRollbackManager : public SyncRollbackManagerBase {
     SyncRollbackManagerBase::InitInternal(
         args->database_location,
         args->internal_components_factory.get(),
+        InternalComponentsFactory::STORAGE_IN_MEMORY,
         args->unrecoverable_error_handler.Pass(),
         args->report_unrecoverable_error_function);
   }
@@ -37,12 +38,16 @@ class SyncRollbackManagerBaseTest : public testing::Test {
     args.database_location = base::FilePath(base::FilePath::kCurrentDirectory);
     args.service_url = GURL("https://example.com/");
     args.internal_components_factory.reset(new TestInternalComponentsFactory(
-        InternalComponentsFactory::Switches(), STORAGE_IN_MEMORY));
+        InternalComponentsFactory::Switches(),
+        InternalComponentsFactory::STORAGE_IN_MEMORY,
+        &storage_used_));
     manager_.Init(&args);
+    EXPECT_EQ(InternalComponentsFactory::STORAGE_IN_MEMORY, storage_used_);
   }
 
   SyncTestRollbackManager manager_;
   base::MessageLoop loop_;    // Needed for WeakHandle
+  InternalComponentsFactory::StorageOption storage_used_;
 };
 
 TEST_F(SyncRollbackManagerBaseTest, InitTypeOnConfiguration) {