function assertConfigEquals(config, widgetConfig) {
  // Create widget config of provided config plain object.
  var temp = new firebaseui.auth.widget.Config();
  temp.setConfig(config);
  // Compare both widget configs.
  assertObjectEquals(temp, widgetConfig);
}
Asserts provided configuration object matches the widget configuration.

@param {?Object} config
@param {firebaseui.auth.widget.Config} widgetConfig