[SyncFS] Implement Database initialization part of SyncEngineInitializer

chrome/browser/sync_file_system/drive_backend/sync_engine_initializer.h

 // 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.
 
 #ifndef CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_INITIALIZER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_INITIALIZER_H_
 
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/sequenced_task_runner.h"
 #include "chrome/browser/sync_file_system/sync_callbacks.h"
 #include "chrome/browser/sync_file_system/sync_task.h"
 
+namespace drive {
+class DriveAPIService;
+}
+
 namespace sync_file_system {
 namespace drive_backend {
 
+class MetadataDatabase;
+
 class SyncEngineInitializer : public SyncTask {
  public:
-  SyncEngineInitializer();
+  SyncEngineInitializer(base::SequencedTaskRunner* task_runner,
+                        drive::DriveAPIService* drive_api,
+                        const base::FilePath& database_path);
   virtual ~SyncEngineInitializer();
   virtual void Run(const SyncStatusCallback& callback) OVERRIDE;
 
  private:
+  void DidCreateMetadataDatabase(const SyncStatusCallback& callback,
+                                 SyncStatusCode status,
+                                 scoped_ptr<MetadataDatabase> instance);
+
+  scoped_refptr<base::SequencedTaskRunner> task_runner_;
+  drive::DriveAPIService* drive_api_;
+  base::FilePath database_path_;
+
+  scoped_ptr<MetadataDatabase> metadata_database_;
+
+  base::WeakPtrFactory<SyncEngineInitializer> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(SyncEngineInitializer);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_INITIALIZER_H_