I've split this off from  crbug.com/706941  which lumped this regression together with a different one.

This one is believed to be caused by:
https://codereview.chromium.org/2770293003

Here's the bisect details:

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

Hi skobes@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 : skobes
  Commit : 56451775d90238d9def5e9663771de8d0ca7ef6f
  Date   : Tue Mar 28 18:46:38 2017
  Subject: Feed ScrollableArea::showOverlayScrollbars into ScrollbarAnimationController.

Bisect Details
  Configuration: android_nexus6_perf_bisect
  Benchmark    : memory.top_10_mobile
  Metric       : memory:chrome:all_processes:reported_by_os:system_memory:java_heap:proportional_resident_size_avg/foreground/https_www_google_co_uk_hl_en_q_science
  Change       : 1.32% | 18407196.4444 -> 18650453.3333

Revision             Result                  N
chromium@460084      18407196 +- 221737      9       good
chromium@460150      18432000 +- 191660      6       good
chromium@460167      18432853 +- 185468      6       good
chromium@460175      18408789 +- 147910      9       good
chromium@460177      18470912 +- 665447      14      good
chromium@460178      18740907 +- 715482      9       bad       <--
chromium@460179      18578091 +- 208414      9       bad
chromium@460183      18763776 +- 919112      9       bad
chromium@460215      18650453 +- 201885      6       bad

Please refer to the following doc on diagnosing memory regressions:
  https://chromium.googlesource.com/chromium/src/+/master/docs/memory-infra/memory_benchmarks.md

To Run This Test
  src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests memory.top_10_mobile

Debug Info
  https://chromeperf.appspot.com/buildbucket_job_status/8980049769329360128

Is this bisect wrong?
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5887561458778112


| O O | Visit http://www.chromium.org/developers/speed-infra/perf-bug-faq
|  X  | for more information addressing perf regression bugs. For feedback,
| / \ | file a bug with component Speed>Bisection.  Thank you!