The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3ebc815673812682541c6f4e7c9a53a7b010ee62

commit 3ebc815673812682541c6f4e7c9a53a7b010ee62
Author: Ned Nguyen <nednguyen@google.com>
Date: Tue Jul 11 13:21:56 2017

[system_health] Remove facebook, tumblr, pinterest, twitter, flickr loading stories

Stories which are removed:
load:social:facebook (mobile + desktop)
load:social:tumblr (mobile + desktop)
load:social:pinterest (mobile)
load:social:twitter (desktop)
load:media:flickr (desktop)

Bug:  725923 
Change-Id: I8d040d8f52c99dd84c0df9323730a67ebe62f077
Reviewed-on: https://chromium-review.googlesource.com/565886
Reviewed-by: Juan Antonio Navarro Pérez <perezju@chromium.org>
Commit-Queue: Ned Nguyen <nednguyen@google.com>
Cr-Commit-Position: refs/heads/master@{#485613}
[modify] https://crrev.com/3ebc815673812682541c6f4e7c9a53a7b010ee62/tools/perf/benchmarks/system_health_smoke_test.py
[modify] https://crrev.com/3ebc815673812682541c6f4e7c9a53a7b010ee62/tools/perf/page_sets/system_health/browsing_stories.py
[modify] https://crrev.com/3ebc815673812682541c6f4e7c9a53a7b010ee62/tools/perf/page_sets/system_health/loading_stories.py