Update profiling.md with link to internal tools

I thought about linking to a shared doc that said these same things,
but this documentation seems to have everything I would want to say.

Change-Id: I027ac5e9f6e5a6925306e405ae36e0c1f6fcf938
Reviewed-on: https://chromium-review.googlesource.com/c/1407948
Reviewed-by: Stefan Zager <szager@chromium.org>
Commit-Queue: enne <enne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622258}
1 file changed