All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=854520

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=25dbfa4416cd3ae03f1db879c20df8533efeef215b02ab6091bf6267ae530d34


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

perf-go-webview-phone

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8943215390117416368

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

Hi jamwalla@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 : James Wallace-Lee
  Commit : fbb0e336a2d6fe1237aecbb9cdfaa59e252857fa
  Date   : Mon Jun 18 23:57:47 2018
  Subject: AW: Don't draw if PrepareTiles is needed and no damage

Bisect Details
  Configuration: go-webview-phone-perf-bisect
  Benchmark    : memory.top_10_mobile
  Metric       : memory:webview:all_processes:reported_by_chrome:cc:effective_size_avg/background/after_http_yandex_ru_touchsearch_text_science
  Change       : 33.33% | 1572864.0 -> 2097152.0

Revision                                       Result              N
android-chrome@8e54c6dbe8                      1572864 +- 0.0      6      good
android-chrome@8e54c6dbe8,chromium@568239      1572864 +- 0.0      6      good
android-chrome@8e54c6dbe8,chromium@568240      2097152 +- 0.0      6      bad       <--
android-chrome@8e54c6dbe8,chromium@568241      2097152 +- 0.0      6      bad
android-chrome@8e54c6dbe8,chromium@568243      2097152 +- 0.0      6      bad
android-chrome@8e54c6dbe8,chromium@568247      2097152 +- 0.0      6      bad
android-chrome@8e54c6dbe8,chromium@568255      2097152 +- 0.0      6      bad
android-chrome@6e1a51a024                      2097152 +- 0.0      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-webview --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests --story-filter=http.yandex.ru.touchsearch.text.science memory.top_10_mobile

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8943215390117416368


For feedback, file a bug with component Speed>Bisection

+boliu, this is probably real, right? I still don't understand how these changes cause memory regressions

more likely test measurement issue than real regression, but who knows

 Issue 855469  has been merged into this issue.

 Issue 855491  has been merged into this issue.

 Issue 855456  has been merged into this issue.

telemetry ergonomics still needs improvement for the case of investigating a regression

--output-format=html generates a file that doesn't open in chrome anymore because localstorage is disabled on file urls. And afaict, still no way to get the trace of a run at the same time (I want to add more trace categories than what the bot has)

I think telemetry probably need to focus a bit more in this area

one of a few graphs already recovered, so looks like unrelated to this.

others show regression in cc memory, but the occasional variance bars, some in tiles and some in "image_memory". my guess without verification is that WillSkipDraw calling OnDraw with empty transform and viewport isn't ok. It should just not update those fields at all, which is just re-ordering a few lines of code

I use args like 
--extra-chrome-categories=disabled-by-default-memory-infra --pause=after-run-story --extra-browser-args="--enable-heap-profiling=native"
to get a little more out of telemetry, but, yeah, not super straightforward

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bee41268fc28e181eb165cd84122a1acc19cbae8

commit bee41268fc28e181eb165cd84122a1acc19cbae8
Author: Bo Liu <boliu@chromium.org>
Date: Wed Jun 27 21:04:33 2018

cc: Skip updating viewport/transform in skip draw

If a draw is skipped, these values do not change, and should just be
ignored.

Bug: 854520
Bug:  687695 
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I1e9582043116f0a5acb7f9217a73a8379b7ac46f
Reviewed-on: https://chromium-review.googlesource.com/1115762
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Commit-Queue: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570898}
[modify] https://crrev.com/bee41268fc28e181eb165cd84122a1acc19cbae8/cc/trees/layer_tree_host_impl.cc
[modify] https://crrev.com/bee41268fc28e181eb165cd84122a1acc19cbae8/cc/trees/layer_tree_host_impl_unittest.cc

That had no effect on anything. Welp.