[SyncFS] Refactor MetadataDatabase on dirty flag handling and sync-root creation

chrome/browser/sync_file_system/drive_backend/metadata_database_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/metadata_database.h"
 
 #include "base/bind.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"
@@ skipping 238 matching lines @@
     PutServiceMetadataToBatch(service_metadata, &batch);
     EXPECT_TRUE(db->Write(leveldb::WriteOptions(), &batch).ok());
   }
 
   FileMetadata CreateSyncRootMetadata() {
     FileMetadata sync_root;
     sync_root.set_file_id(kSyncRootFolderID);
     FileDetails* details = sync_root.mutable_details();
     details->set_title(kSyncRootFolderTitle);
     details->set_file_kind(FILE_KIND_FOLDER);
+    details->set_change_id(current_change_id_);
     return sync_root;
   }
 
   FileMetadata CreateFileMetadata(const FileMetadata& parent,
                                   const std::string& title) {
     FileMetadata file;
     file.set_file_id(GenerateFileID());
     FileDetails* details = file.mutable_details();
     details->add_parent_folder_ids(parent.file_id());
     details->set_title(title);
@@ skipping 305 matching lines @@
         app_root_folders,
         CreateResultReceiver(&status));
     message_loop_.RunUntilIdle();
     return status;
   }
 
   void ResetTrackerID(FileTracker* tracker) {
     tracker->set_tracker_id(GetTrackerIDByFileID(tracker->file_id()));
   }
 
+  int64 current_change_id() const {
+    return current_change_id_;
+  }
+
  private:
   base::ScopedTempDir database_dir_;
   base::MessageLoop message_loop_;
 
   scoped_ptr<leveldb::Env> in_memory_env_;
   scoped_ptr<MetadataDatabase> metadata_database_;
 
   int64 current_change_id_;
   int64 next_tracker_id_;
   int64 next_file_id_number_;
@@ skipping 465 matching lines @@
 
 TEST_F(MetadataDatabaseTest, PopulateInitialDataTest) {
   TrackedFile sync_root(CreateTrackedSyncRoot());
   TrackedFile app_root(CreateTrackedFolder(sync_root, "app_root"));
   app_root.tracker.set_active(false);
 
   const TrackedFile* tracked_files[] = {
     &sync_root, &app_root
   };
 
-  int64 largest_change_id = 42;
   scoped_ptr<google_apis::FileResource> sync_root_folder(
       CreateFileResourceFromMetadata(sync_root.metadata));
   scoped_ptr<google_apis::FileResource> app_root_folder(
       CreateFileResourceFromMetadata(app_root.metadata));
 
   ScopedVector<google_apis::FileResource> app_root_folders;
   app_root_folders.push_back(app_root_folder.release());
 
   EXPECT_EQ(SYNC_STATUS_OK, InitializeMetadataDatabase());
   EXPECT_EQ(SYNC_STATUS_OK, PopulateInitialData(
-      largest_change_id,
+      current_change_id(),
       *sync_root_folder,
       app_root_folders));
 
   ResetTrackerID(&sync_root.tracker);
   ResetTrackerID(&app_root.tracker);
   app_root.tracker.set_parent_tracker_id(sync_root.tracker.tracker_id());
 
   VerifyTrackedFiles(tracked_files, arraysize(tracked_files));
   VerifyReloadConsistency();
 }
@@ skipping 27 matching lines @@
   EXPECT_TRUE(file->HasKey("details"));
 
   ASSERT_TRUE(files->GetDictionary(1, &file));
   EXPECT_TRUE(file->GetString("title", &str) && str == "file_0");
   EXPECT_TRUE(file->GetString("type", &str) && str == "file");
   EXPECT_TRUE(file->HasKey("details"));
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system