- Electron version: 1.1.0
- Operating system: N/A

Currently there isn't any way to remove dialog boxes (such as ones created through `dialog.showMessageBox`).  This can be useful in, for example, "Keep Waiting" dialogs.  After the window becomes responsive again it would be great if we could programmatically close the dialog.

shell/browser/api/electron_api_dialog.cc
const electron::MessageBoxSettings& settings,
    gin::Arguments* args) {
  v8::Isolate* isolate = args->isolate();
  gin_helper::Promise<gin_helper::Dictionary> promise(isolate);
  v8::Local<v8::Promise> handle = promise.GetHandle();
  electron::ShowMessageBox(
      settings, base::BindOnce(&ResolvePromiseObject, std::move(promise)));
  return handle;
}
void ShowOpenDialogSync(const file_dialog::DialogSettings& settings,
                        gin::Arguments* args) {
  std::vector<base::FilePath> paths;
  if (file_dialog::ShowOpenDialogSync(settings, &paths))
    args->Return(paths);
}
v8::Local<v8::Promise> ShowOpenDialog(
    const file_dialog::DialogSettings& settings,
    gin::Arguments* args) {
  gin_helper::Promise<gin_helper::Dictionary> promise(args->isolate());
  v8::Local<v8::Promise> handle = promise.GetHandle();
  file_dialog::ShowOpenDialog(settings, std::move(promise));
  return handle;
}
void ShowSaveDialogSync(const file_dialog::DialogSettings& settings,
                        gin::Arguments* args) {
  base::FilePath path;
  if (file_dialog::ShowSaveDialogSync(settings, &path))
    args->Return(path);
}
v8::Local<v8::Promise> ShowSaveDialog(