Looking into this now. The story runs without issues locally. Running try jobs on a few bots now: https://codereview.chromium.org/2612693003/

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/896cea0b12a742f9375ed81590f789eedd48d58f

commit 896cea0b12a742f9375ed81590f789eedd48d58f
Author: perezju <perezju@chromium.org>
Date: Thu Jan 05 12:46:55 2017

[system health] Re-enable browse:media:youtube

Trybot and local runs show that the benchmark works correctly
now.

BUG= 661775 
TBR=nednguyen@google.com

Review-Url: https://codereview.chromium.org/2612693003
Cr-Commit-Position: refs/heads/master@{#441635}

[modify] https://crrev.com/896cea0b12a742f9375ed81590f789eedd48d58f/tools/perf/page_sets/system_health/browsing_stories.py