client/lib/analytics/ad-tracking.js
function recordViewCheckoutInCriteo( cart ) {
	if ( ! isAdTrackingAllowed() || ! isCriteoEnabled ) {
		return;
	}

	if ( cart.is_signup ) {
		return;
	}

	// Note that unlike `recordOrderInCriteo` above, this doesn't include the order id
	const params = [
		'viewBasket',
		{
			currency: cart.currency,
			item: cartToCriteoItems( cart ),
		},
	];
	debug( 'recordViewCheckoutInCriteo:', params );
	recordInCriteo( ...params );
}
function recordViewCheckoutInCriteo( cart ) {
	if ( ! isAdTrackingAllowed() || ! isCriteoEnabled ) {
		return;
	}

	if ( cart.is_signup ) {
		return;
	}

	// Note that unlike `recordOrderInCriteo` above, this doesn't include the order id
	const params = [
		'viewBasket',
		{
			currency: cart.currency,
			item: cartToCriteoItems( cart ),
		},
	];
	debug( 'recordViewCheckoutInCriteo:', params );
	recordInCriteo( ...params );
}
Records that a user viewed the checkout page

@param {Object} cart - cart as `CartValue` object
@returns {void}