All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=706957

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg7OjH7QkM


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

android-nexus5X

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8983669838558093200

=== BISECT JOB RESULTS ===
Perf regression found but unable to narrow commit range

Build failures prevented the bisect from narrowing the range further.


Bisect Details
  Configuration: android_nexus5X_perf_bisect
  Benchmark    : smoothness.key_mobile_sites_smooth
  Metric       : first_gesture_scroll_update_latency/first_gesture_scroll_update_latency

Suspected Commit Range
  99 commits in range
  https://chromium.googlesource.com/chromium/src/+log/958a4bb090a8f57113d094be99b573c036ecb1e0..aa9787bbd7919d6114c6bb40fe8e30cdae424ba1


Revision             Result                  N
chromium@458869      16.9558 +- 10.6696      14       good
chromium@458870      ---                     ---      build failure
---                  ---                     ---      too many build failures to list
chromium@458967      ---                     ---      build failure
chromium@458968      21.659 +- 4.86047       9        bad

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 smoothness.key_mobile_sites_smooth

Debug Info
  https://chromeperf.appspot.com/buildbucket_job_status/8983669838558093200

Is this bisect wrong?
  https://chromeperf.appspot.com/bad_bisect?try_job_id=6061113206112256


| 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!

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8983293668945070880

=== BISECT JOB RESULTS ===
Perf regression found but unable to narrow commit range

Build failures prevented the bisect from narrowing the range further.


Bisect Details
  Configuration: android_nexus5X_perf_bisect
  Benchmark    : smoothness.key_mobile_sites_smooth
  Metric       : first_gesture_scroll_update_latency/first_gesture_scroll_update_latency

Suspected Commit Range
  99 commits in range
  https://chromium.googlesource.com/chromium/src/+log/958a4bb090a8f57113d094be99b573c036ecb1e0..aa9787bbd7919d6114c6bb40fe8e30cdae424ba1


Revision             Result                  N
chromium@458869      16.4765 +- 7.90645      9        good
chromium@458870      ---                     ---      build failure
---                  ---                     ---      too many build failures to list
chromium@458967      ---                     ---      build failure
chromium@458968      21.7039 +- 3.95556      6        bad

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 smoothness.key_mobile_sites_smooth

Debug Info
  https://chromeperf.appspot.com/buildbucket_job_status/8983293668945070880

Is this bisect wrong?
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5800085092302848


| 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!

So bisect is useless here. Adding a few folks who might know what's up. Please take a look at the regression range and let me know if anything stands out.

The only thing in the Skia roll that strikes me as a possibility is brianosman@'s change, but even that seems pretty unlikely.

https://skia.googlesource.com/skia.git/+/ce425510a07632f14b7b779ec3864f719cb4326b

Chong, I assume that's https://chromium.googlesource.com/chromium/src/+/5a7f45dab8372cb7b80ee24dfb137a7ced2049ea ?

Re #8: Yes it sounds similar to  issue 704732 . The CL has been reverted and I'm working on the fix.