Update metrics_daemon to use base/time.h instead of time_t directly.

Also, guard against time jumps in the active daily use metric collection.

BUG=none
TEST=unit tests; gmerge'd on the target device and inspected the logs.

Review URL: http://codereview.chromium.org/2576005
3 files changed
tree: 55fadad34819781bbf0adb6895ca5b157ce5b25f
  1. metrics/