All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=771273

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=fa6732218e8840955c3809a33ec26647e677875e48fc1c41638edcf2383ab25f


Bot(s) for this bug's original alert(s):

chromium-rel-mac11
chromium-rel-mac11-air
chromium-rel-mac11-pro
chromium-rel-mac12
chromium-rel-mac12-mini-8gb
chromium-rel-win10
chromium-rel-win7-dual
chromium-rel-win7-gpu-ati
chromium-rel-win7-gpu-intel
chromium-rel-win7-gpu-nvidia
chromium-rel-win7-x64-dual
chromium-rel-win8-dual
win-high-dpi

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8966730133902245248

=== Auto-CCing suspected CL author delphick@chromium.org ===

Hi delphick@chromium.org, the bisect results pointed to your CL, please take a look at the
results.


=== BISECT JOB RESULTS ===
Perf regression found with culprit

Suspected Commit
  Author : Dan Elphick
  Commit : 906e13713d20602f2af24511d945c5c53eaad3d6
  Date   : Fri Sep 29 00:36:49 2017
  Subject: Convert BackgroundFetchDelegateImpl to use DownloadService

Bisect Details
  Configuration: mac_10_11_perf_bisect
  Benchmark    : media.tough_video_cases_tbmv2
  Metric       : memory:chrome:all_processes:reported_by_chrome:sqlite:effective_size_avg/memory:chrome:all_processes:reported_by_chrome:sqlite:effective_size_avg
  Change       : 4.69% | 423476.053333 -> 443337.6

Revision             Result                 N
chromium@505194      423476 +- 2323.75      6      good
chromium@505218      423515 +- 1764.16      6      good
chromium@505224      423100 +- 893.383      6      good
chromium@505227      424012 +- 2051.14      6      good
chromium@505229      423196 +- 1865.94      6      good
chromium@505230      443495 +- 1020.47      6      bad       <--
chromium@505241      443161 +- 1148.13      6      bad
chromium@505288      443338 +- 1548.77      6      bad

To Run This Test
  src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests media.tough_video_cases_tbmv2

More information on addressing performance regressions:
  http://g.co/ChromePerformanceRegressions

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8966730133902245248


For feedback, file a bug with component Speed>Bisection

Not sure how I missed this, but it seems unlikely this change would have affected anything directly since it's behind a flag and requires the use of a specific API.