metrics: move sample file from /var/run to /var/lib

Some metrics are generated near shutdown and we expect to collect
them at reboot, but /var/run is a tmpfs and /var/run/uma-events
is lost.

This changes the uma events file location from the perspective
of the metrics daemon.  I am making the same change to Chrome.
I am adding a symlink to allow an older Chrome to read the
samples from the old location.  A newer Chrome will be screwed
but I hope that's OK (i.e. this will work for official builds
and for Chrome OS developers, but may cause malfunction for
Chrome developers)

TEST=verified that /var/lib/metrics/uma-events grows and is truncated

Change-Id: I677cda16486de239dd205247083d4ad7240d992b
Reviewed-by: Luigi Semenzato <>
Tested-by: Luigi Semenzato <>
Commit-Queue: Luigi Semenzato <>
3 files changed
tree: 2fbb7ac294d5b38284f5704a88ce5a4c9a530b79
  1. metrics/