brillo: Test required power management interfaces present

Add test brillo_PowerMgmtInterfaces, which verifies the power management
interfaces required by the DPS are present:

* kernel wakelocks: verify the wakelock sysfs interface is present.
  N.B.: It is not possible to build a brillo kernel without support.

* cpufreq: verify CPU 0's cpufreq sysfs interface is present, and has
  at least one scaling governor available.

* cpuidle: verify the cpuidle sysfs interface is present and a cpuidle
  driver is registered.

This test is added to the Brillo BVT, but not smoke tests, as the Brillo
emulator does not meet all of the above requirements.

Bug: 26163706
Change-Id: I21943dcd9412fb37aae57d75e64aed890fd9c057
Commit-Ready: Todd Poynor <>
Tested-by: Todd Poynor <>
Reviewed-by: Dan Erat <>
2 files changed