Setting the policy specifies the length of time in milliseconds without user input after which the screen locks when running on AC power or battery. Values are clamped to be less than the idle delay in PowerManagementIdleSettings.
When set to zero, Google Chrome OS doesn't lock the screen when the user becomes idle. If unset, a default time is used.
Recommendation: Lock the screen on idle by turning on screen locking on suspend and have Google Chrome OS suspend after the idle delay. Only use this policy when screen locking should occur a significant amount of time sooner than suspend or when you don't want suspend on idle.
See https://cloud.google.com/docs/chrome-enterprise/policies/?policy=ScreenLockDelays for more information about schema and formatting.