user_activity: Computed the metrics for the common functions.

Integrated the script with the utils module.

BUG=None
TEST=None

Change-Id: I4c8d0bdbda6df5996eae873655cfaf355cf559a2
Reviewed-on: https://chrome-internal-review.googlesource.com/290455


Reviewed-by: Luis Lozano <llozano@chromium.org>
Reviewed-by: Evelina Dumitrescu <evelinad@google.com>
Tested-by: Evelina Dumitrescu <evelinad@google.com>
Reviewed-on: https://chromium-review.googlesource.com/435916


Commit-Ready: Luis Lozano <llozano@chromium.org>
Tested-by: Luis Lozano <llozano@chromium.org>