Android: Simplify power metrics collection Also check for missing values and dupes Bug: b/291604008 Change-Id: I909ca2bf53d3aa0bf5ba66f7168e9925cfd7da3c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4685323 Reviewed-by: Cody Northrop <cnorthrop@google.com> Commit-Queue: Roman Lavrov <romanl@google.com>