All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=753246

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=21a5640ed8e911e74584a00103a4527ed3f2d66ae783675a8180ced92f0d3771


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

android-webview-nexus5X

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8971855100877187056

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8971855048855087600

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

Hi thomasanderson@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 : Tom Anderson
  Commit : 4e33415240d57999459a2b9376831fa1303eabac
  Date   : Sat Aug 05 00:06:59 2017
  Subject: Remove usage of readdir_r() in Chromium code

Bisect Details
  Configuration: android_webview_arm64_aosp_perf_bisect
  Benchmark    : speedometer2
  Metric       : Inferno-TodoMVC/Speedometer2
  Change       : 2.12% | 5059.9025 -> 4959.925

Revision             Result                  N
chromium@492160      5059.9 +- 108.263       14      good
chromium@492177      5048.11 +- 181.98       14      good
chromium@492186      5038.4 +- 60.6407       9       good
chromium@492188      5036.0 +- 102.15        9       good
chromium@492189      5043.51 +- 181.07       14      good
chromium@492190      4976.17 +- 146.608      9       bad       <--
chromium@492194      4973.8 +- 220.557       14      bad
chromium@492227      4959.92 +- 66.065       6       bad

To Run This Test
  src/tools/perf/run_benchmark -v --browser=android-webview --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests --story-filter=Speedometer2 speedometer2

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8971855100877187056


For feedback, file a bug with component Speed>Bisection

=== Auto-CCing suspected CL author pdfium-deps-roller@chromium.org ===

Hi pdfium-deps-roller@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 : pdfium-deps-roller@chromium.org
  Commit : eb901d2f1051fc2661bf369e390895b9555d9f23
  Date   : Sat Aug 05 01:49:30 2017
  Subject: Roll src/third_party/pdfium/ df950b87e..bd456561f (1 commit)

Bisect Details
  Configuration: android_webview_arm64_aosp_perf_bisect
  Benchmark    : speedometer2
  Metric       : Total/Speedometer2
  Change       : 0.84% | 32664.6283333 -> 32388.7487037

Revision             Result                  N
chromium@492160      32664.6 +- 476.628      9       good
chromium@492194      32740.6 +- 644.22       14      good
chromium@492201      32660.2 +- 622.241      21      good
chromium@492208      32633.6 +- 507.883      21      good
chromium@492210      32663.2 +- 538.061      14      good
chromium@492211      32512.5 +- 423.334      14      bad       <--
chromium@492227      32388.7 +- 465.006      9       bad

To Run This Test
  src/tools/perf/run_benchmark -v --browser=android-webview --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests --story-filter=Speedometer2 speedometer2

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8971855048855087600


For feedback, file a bug with component Speed>Bisection

+thestig for pdfium roll

PDFium isn't used on Android. That can't be the culprit.

This recovered again.