UKM fills out a minimal system profile using the MetricsLog::RecordCoreSystemProfile method.

However, some fields set in this method, such as hardware.hardware_class, are normally overridden in a platform-specific metrics provider on ChromeOS.

ChromeOSMetricsProvider::ProvideSystemProfileMetrics sets hardware.hardware_class using cros-specific logic, for example.

This cros-specific logic is not exercised when using UKM, which calls RecordCoreSystemProfile unconditionally on all platforms.

The end result is that hardware_class is unset on cros, and this confuses some of our code that determines which platform a given client uses, which expects hardware_class to be set for cros.

We should audit which SystemProfile fields can be set by platform-specific providers and make sure we exercise all platform-specific logic when filling out the system profile in UKM.