Computer Configuration > Administrative Templates > Google Chrome
Both
HKLM\Software\Policies\Google\Chrome
Setting the policy to Enabled turns off data synchronization in Google Chrome using Google-hosted synchronization services. To fully turn off Chrome Sync services, we recommend that you turn off the service in the Google Admin console. If the policy is set to Disabled or not set, users are allowed to choose whether to use Chrome Sync. Note: Do not turn on this policy when RoamingProfileSupportEnabled is Enabled, because that feature shares the same client-side functionality. The Google-hosted synchronization is off completely in this case.