Process HISTOGRAM line of the test result

Doing the same thing as Chromium's performance_log_processor.py.
https://chromium.googlesource.com/chromium/tools/build/+/master/scripts/slave/performance_log_processor.py

BUG=chromium:433442
TEST=test_that -b ${board} --args='local=True' ${host} telemetry_Benchmarks.tab_switching.top_10

Change-Id: Ic3af442df28a5225a2f572b35bf6a31f5193c262
Reviewed-on: https://chromium-review.googlesource.com/234653
Trybot-Ready: Ryo Hashimoto <hashimoto@chromium.org>
Tested-by: Ryo Hashimoto <hashimoto@chromium.org>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Commit-Queue: Ryo Hashimoto <hashimoto@chromium.org>
1 file changed