$feed_service = $this->getService(FeedService::class);
$feed = new Feed();
$feed->setName('GMB');
$feedData = new PlacesLocationFeedData();
$feedData->setEmailAddress('***');
$feedData->setBusinessAccountIdentifier('***');
$oAuthInfo = new OAuthInfo();
$oAuthInfo->setHttpMethod('GET');
$oAuthInfo->setHttpRequestUrl('https://www.googleapis.com/auth/plus.business.manage');
$oAuthInfo->setHttpAuthorizationHeader('Bearer '.$gmb->getAccessToken());
$feedData->setOAuthInfo($oAuthInfo);
$feed->setSystemFeedGenerationData($feedData);
$feed->setOrigin(FeedOrigin::ADWORDS);
$feed_operation = new FeedOperation();
$feed_operation->setOperand($feed);
$feed_operation->setOperator(Operator::ADD);
$feed_service->mutate(array($feed_operation));