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

chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc

Index: chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
diff --git a/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc b/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
index 604ba6ee489c5d989bb3bc86eee3c5d344711e60..8f1d7ee66519f65cbc0cd2ba4c937b644596a6d3 100644
--- a/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
@@ -256,6 +256,7 @@ class MetadataDatabaseTest : public testing::Test {
     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;
   }
 
@@ -581,6 +582,10 @@ class MetadataDatabaseTest : public testing::Test {
     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_;
@@ -1066,7 +1071,6 @@ TEST_F(MetadataDatabaseTest, PopulateInitialDataTest) {
     &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(
@@ -1077,7 +1081,7 @@ TEST_F(MetadataDatabaseTest, PopulateInitialDataTest) {
 
   EXPECT_EQ(SYNC_STATUS_OK, InitializeMetadataDatabase());
   EXPECT_EQ(SYNC_STATUS_OK, PopulateInitialData(
-      largest_change_id,
+      current_change_id(),
       *sync_root_folder,
       app_root_folders));