[SyncFS] Make MetadataDatabase operations synchronous

chrome/browser/sync_file_system/drive_backend/sync_engine_initializer_unittest.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 "chrome/browser/sync_file_system/drive_backend/sync_engine_initializer.h"
 
 #include "base/bind.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/run_loop.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 89 matching lines @@
                          SyncStatusCode status) {
     *status_out = status;
     metadata_database_ = initializer->PassMetadataDatabase();
   }
 
   SyncStatusCode PopulateDatabase(
       const google_apis::FileResource& sync_root,
       const google_apis::FileResource** app_roots,
       size_t app_roots_count) {
     SyncStatusCode status = SYNC_STATUS_UNKNOWN;
-    scoped_ptr<MetadataDatabase> database;
-    MetadataDatabase::Create(
-        database_path(),
-        in_memory_env_.get(),
-        CreateResultReceiver(&status, &database));
-    base::RunLoop().RunUntilIdle();
+    scoped_ptr<MetadataDatabase> database = MetadataDatabase::Create(
+        database_path(), in_memory_env_.get(), &status);
     if (status != SYNC_STATUS_OK)
       return status;
 
     // |app_root_list| must not own the resources here. Be sure to call
     // weak_clear later.
     ScopedVector<google_apis::FileResource> app_root_list;
     for (size_t i = 0; i < app_roots_count; ++i) {
       app_root_list.push_back(
           const_cast<google_apis::FileResource*>(app_roots[i]));
     }
 
-    status = SYNC_STATUS_UNKNOWN;
-    database->PopulateInitialData(kInitialLargestChangeID,
-                                  sync_root,
-                                  app_root_list,
-                                  CreateResultReceiver(&status));
-    base::RunLoop().RunUntilIdle();
+    status = database->PopulateInitialData(
+        kInitialLargestChangeID, sync_root, app_root_list);
 
     app_root_list.weak_clear();
-
-    return SYNC_STATUS_OK;
+    return status;
   }
 
   scoped_ptr<google_apis::FileResource> CreateRemoteFolder(
       const std::string& parent_folder_id,
       const std::string& title) {
     google_apis::GDataErrorCode error = google_apis::GDATA_OTHER_ERROR;
     scoped_ptr<google_apis::FileResource> entry;
     sync_context_->GetDriveService()->AddNewDirectory(
         parent_folder_id, title,
         drive::DriveServiceInterface::AddNewDirectoryOptions(),
@@ skipping 202 matching lines @@
 
   EXPECT_EQ(0u, CountTrackersForFile(sync_root->file_id()));
   EXPECT_FALSE(HasNoParent(sync_root->file_id()));
 
   EXPECT_EQ(1u, CountFileMetadata());
   EXPECT_EQ(1u, CountFileTracker());
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system