[SyncFS] Make MetadataDatabase operations synchronous

chrome/browser/sync_file_system/drive_backend/conflict_resolver.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/conflict_resolver.h"
 
 #include "base/callback.h"
 #include "base/format_macros.h"
 #include "base/location.h"
 #include "base/logging.h"
@@ skipping 250 matching lines @@
     SyncTaskManager::NotifyTaskDone(token.Pass(), status);
     return;
   }
 
   deleted_file_ids_.push_back(file_id);
   if (!non_primary_file_ids_.empty()) {
     RemoveNonPrimaryFiles(token.Pass());
     return;
   }
 
-  metadata_database()->UpdateByDeletedRemoteFileList(
-      deleted_file_ids_, SyncTaskToken::WrapToCallback(token.Pass()));
+  status = metadata_database()->UpdateByDeletedRemoteFileList(
+      deleted_file_ids_);
+  SyncTaskManager::NotifyTaskDone(token.Pass(), status);
 }
 
 bool ConflictResolver::IsContextReady() {
   return sync_context_->GetDriveService() &&
       sync_context_->GetMetadataDatabase();
 }
 
 void ConflictResolver::UpdateFileMetadata(
     const std::string& file_id,
     scoped_ptr<SyncTaskToken> token) {
   drive_service()->GetFileResource(
       file_id,
       base::Bind(&ConflictResolver::DidGetRemoteMetadata,
                  weak_ptr_factory_.GetWeakPtr(), file_id,
                  base::Passed(&token)));
 }
 
 void ConflictResolver::DidGetRemoteMetadata(
     const std::string& file_id,
     scoped_ptr<SyncTaskToken> token,
     google_apis::GDataErrorCode error,
     scoped_ptr<google_apis::FileResource> entry) {
   SyncStatusCode status = GDataErrorCodeToSyncStatusCode(error);
   if (status != SYNC_STATUS_OK && error != google_apis::HTTP_NOT_FOUND) {
     SyncTaskManager::NotifyTaskDone(token.Pass(), status);
     return;
   }
 
   if (error != google_apis::HTTP_NOT_FOUND) {
-    metadata_database()->UpdateByDeletedRemoteFile(
-        file_id, SyncTaskToken::WrapToCallback(token.Pass()));
+    status = metadata_database()->UpdateByDeletedRemoteFile(file_id);
+    SyncTaskManager::NotifyTaskDone(token.Pass(), status);
     return;
   }
 
   if (!entry) {
     NOTREACHED();
     SyncTaskManager::NotifyTaskDone(token.Pass(), SYNC_STATUS_FAILED);
     return;
   }
 
-  metadata_database()->UpdateByFileResource(
-      *entry, SyncTaskToken::WrapToCallback(token.Pass()));
+  status = metadata_database()->UpdateByFileResource(*entry);
+  SyncTaskManager::NotifyTaskDone(token.Pass(), status);
 }
 
 drive::DriveServiceInterface* ConflictResolver::drive_service() {
   set_used_network(true);
   return sync_context_->GetDriveService();
 }
 
 MetadataDatabase* ConflictResolver::metadata_database() {
   return sync_context_->GetMetadataDatabase();
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system