drive: CreateDirectory should only wait for its parent directory's load.

Previously it was waiting for the full Drive tree to load,
which takes unnecessarily long time.

BUG=283901
R=hidehiko@chromium.org

Review URL: https://codereview.chromium.org/23861006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221365 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/drive/file_system.cc

@@ -455,8 +455,9 @@ void FileSystem::CreateDirectory(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!callback.is_null());
 
-  change_list_loader_->LoadIfNeeded(
-      internal::DirectoryFetchInfo(),
+  // Ensure its parent directory is loaded to the local metadata.
+  LoadDirectoryIfNeeded(
+      directory_path.DirName(),
       base::Bind(&FileSystem::CreateDirectoryAfterLoad,
                  weak_ptr_factory_.GetWeakPtr(),
                  directory_path, is_exclusive, is_recursive, callback));