Remove user_activity_benchmarks.

It's going to be hosted in CWP.

BUG=None
TEST=None

Change-Id: I16374dd23e6871f4cf3ab5665b6f7b71336175b1
Reviewed-on: https://chromium-review.googlesource.com/456517
Commit-Ready: Ting-Yuan Huang <laszio@chromium.org>
Tested-by: Ting-Yuan Huang <laszio@chromium.org>
Reviewed-by: Luis Lozano <llozano@chromium.org>
36 files changed