Installing Google Chrome with system wide automatic updates on Microsoft Windows
The official way to use Google chrome in the enterprise is to download the MSI from here. Google has some documentation on how to deploy and configure Chrome policies.
Chrome can still be installed system wide with automatic, unattended upgrades. You can chose a regular system wide installer or a full MSI package and proceed with the download to receive a version of Chrome with the system wide updater.
To clarify, when installed this way, Google Chrome will keep itself current and safe, even if only limited users ever are logged on to Windows. Google Update is a service, which runs regularly with System privileges as a Scheduled Task to check for updates.