All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=776712

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=f8e009d20f9a1ef0a9a3ab1dd62e2364d50ada6df712397d2f6949d5b21d60ee


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

android-nexus5
android-nexus5X
android-nexus6
android-nexus7v2
android-webview-nexus5X
android-webview-nexus6
chromium-rel-mac11-air
chromium-rel-win7-dual
chromium-rel-win7-x64-dual

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8965212524984653040

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

Hi vmpstr@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 : Vladimir Levin
  Commit : 9167e1c4eb3a1b6d094399e35efe427185303428
  Date   : Wed Oct 18 21:28:24 2017
  Subject: cc: Plumb decoding mode state to checker image tracker.

Bisect Details
  Configuration: android_nexus5_perf_bisect
  Benchmark    : smoothness.image_decoding_cases
  Metric       : mean_frame_time/yuv_decoding.html
  Change       : 250.35% | 17.6486666667 -> 61.8325

Revision             Result                   N
chromium@509852      17.6487 +- 0.577288      6      good
chromium@509868      17.5328 +- 0.516018      6      good
chromium@509876      17.7622 +- 1.10291       6      good
chromium@509878      17.3607 +- 0.310476      6      good
chromium@509879      59.7915 +- 0.861154      6      bad       <--
chromium@509880      60.0557 +- 1.30199       6      bad
chromium@509883      59.3323 +- 0.517978      6      bad
chromium@509914      59.8673 +- 2.05145       6      bad
chromium@509975      61.8325 +- 1.12058       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 --story-filter=yuv.decoding.html smoothness.image_decoding_cases

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8965212524984653040


For feedback, file a bug with component Speed>Bisection

 Issue 776960  has been merged into this issue.

The CL in question causes us to veto more decoding cases compared to before. The images were being checkered before and now they are not. The regression as a result of that is expected.

+khushalsagar to confirm, but I think this is a WontFix.

Yup. All regressions are from https://cs.chromium.org/chromium/src/tools/perf/page_sets/image_decoding_cases/yuv_decoding.html. The change in question forces sync decoding from images updated in the DOM by changing the src of an existing element. This puts the image decode on the critical path and will adversely affect the frame rate.