public static function getDefaultGoogleStorageBucketName() {
    $success = false;
    $default_bucket_name = apc_fetch(self::GS_DEFAULT_BUCKET_APC_KEY, $success);
    if ($success) {
      return $default_bucket_name;
    }

    $request = new GetDefaultGcsBucketNameRequest();
    $response = new GetDefaultGcsBucketNameResponse();

    ApiProxy::makeSyncCall('app_identity_service',
                           'GetDefaultGcsBucketName',
                           $request,
                           $response);

    $default_bucket_name = $response->getDefaultGcsBucketName();
    if ($default_bucket_name) {
      apc_store(self::GS_DEFAULT_BUCKET_APC_KEY, $default_bucket_name);
    }
    return $default_bucket_name;
  }