libbrillo: Add daemon logging util functions.

These functions are duplicated today between power_manager and biod in
ChromeOS platform2. I'd like to use these for metrics_daemon as well,
and copying and pasting these again seemed wrong.

TEST=Built metrics_daemon using these functions.

Change-Id: I3cd46dc7f1f5543ac3bd4cf24420d468bb13ff98
Commit-Ready: Justin TerAvest <>
Tested-by: Justin TerAvest <>
Reviewed-by: Dan Erat <>
2 files changed