Since all categories are now statically defined, there's no need to warm
any of them up explicitly in order for the categories to show up in the
tracing UI.

Depends on https://chromium-review.googlesource.com/c/chromium/src/+/1401273.

Bug: chromium:914579
Change-Id: I8ae8977130ae89d6ee3351194ad258d13f3c14f4
Reviewed-on: https://chromium-review.googlesource.com/c/1402779Reviewed-by: Alexei Filippov <alph@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58699}