/** Add files to the Git index. */
 public static void addFiles(
     @NotNull Project project, @NotNull VirtualFile root, @NotNull Collection<VirtualFile> files)
     throws VcsException {
   addPaths(project, root, VcsFileUtil.chunkFiles(root, files));
   updateUntrackedFilesHolderOnFileAdd(project, root, files);
 }