This CL starts to track measurements of time for forced GC
and idle GC.
Before this CL, OilpanGCTimes metric measured time for
'precise' and 'conservative' GC, but now Oilpan GC can run for
other reasons, and some tests need to measure such 'other' GC runs.
In short, we had ['precise', 'conervative'] metrics, and
we will have ['precise', 'conervative', 'forced', 'idle']
metrics.
BUG=438074
TEST=./tools/perf/run_tests oilpan --browser=content-shell-release
Review URL: https://codereview.chromium.org/968773002
Cr-Commit-Position: refs/heads/master@{#323651}
2 files changed
