Collect CPU frequency thermal throttling stats

This collects the max frequency every 30s and reports
it as a percentage of the unthrottled frequency.
The special value of 101% indicates that the CPU is
using turbo.

TEST=ran manually, checked about:histograms

Change-Id: Ia1c8a2344b81b8274f9045b854d2e6d35cf49339
Reviewed-by: Darin Petkov <>
Commit-Queue: Luigi Semenzato <>
Tested-by: Luigi Semenzato <>
4 files changed
tree: 0df3d7bd371579f20fbabc870100c923dc7fa15e
  1. metrics/