Temporary commit to evaluate perf impact of prototype CPU profiler

Design doc: https://docs.google.com/document/d/1Bv-I1yM9AjgY3t27ixdyWHCAW9IpVx02YQ-nSbIqccc

BUG=

Review URL: https://codereview.chromium.org/888923004

Cr-Commit-Position: refs/heads/master@{#315196}
8 files changed