shill: add cumulative metrics for time online
This uses the CumulativeMetrics class to accumulate
and report daily connectivity on a per-technology basis
(wifi, cellular, ...). The new histograms report (at most)
one sample per day per device, and each sample indicates
how much (active) time the device spent connected via
various types of technology.
To test this, I ran it on a device for > 24 hours, switching
between WiFi and Ethernet, and verified that the histograms
samples were as expected.
TEST=manual (see above)
Commit-Ready: Luigi Semenzato <firstname.lastname@example.org>
Tested-by: Luigi Semenzato <email@example.com>
Reviewed-by: Luigi Semenzato <firstname.lastname@example.org>
Reviewed-by: Kirtika Ruchandani <email@example.com>
3 files changed