Using function ids is more reliable since there can be several functions
or scripts with the same name. Also, that way we do not have to parse
anything.

Change-Id: If657141d0d6e27dabb49456e0275cce65e753541
Reviewed-on: https://chromium-review.googlesource.com/c/1267496Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56431}