Add to_snake_case function in make_instrumenting_probes.py

The primary motivation is that the data member names are not following
proper naming conventions within probe_sink.h.tmpl and
instrumenting_probes_impl.cc.tmpl.

This CL add to_snake_case function in make_instrumenting_probes.py to
convert data members to snake case format.

Bug: 936684
Change-Id: I9934aec12dfd85094335078f7c1784f56d6aafac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1524801
Commit-Queue: Abhijeet Kandalkar <abhijeet@igalia.com>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641094}
3 files changed