It's going to be removed from Chromium, see https://crbug.com/812523.

/cc @electron/code-owners 
shell/browser/api/electron_api_app.cc
const std::string& name,
                  const base::FilePath& path) {
  if (!path.IsAbsolute()) {
    thrower.ThrowError("Path must be absolute");
    return;
  }
  bool succeed = false;
  int key = GetPathConstant(name);
  if (key >= 0) {
    succeed =
        base::PathService::OverrideAndCreateIfNeeded(key, path, true, false);
    if (key == DIR_USER_DATA) {
      succeed |= base::PathService::OverrideAndCreateIfNeeded(
          chrome::DIR_USER_DATA, path, true, false);
      succeed |= base::PathService::Override(
          chrome::DIR_APP_DICTIONARIES,
          path.Append(base::FilePath::FromUTF8Unsafe("Dictionaries")));
    }
  }
  if (!succeed)
    thrower.ThrowError("Failed to set path");
}
void App::SetDesktopName(const std::string& desktop_name) {