All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=901390

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=14aa34e62fe40ccaba8bfdd5a7119d97c4c627fcacf86d12a02fd5c6d2554ed3


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

Win 7 Perf

system_health.memory_desktop - Benchmark documentation link:
  https://bit.ly/system-health-benchmarks

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/161cc731e40000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/161cc731e40000

Disallow libjpeg_turbo downscaling of images with non-whole MCUs. by andrescj@chromium.org
https://chromium.googlesource.com/chromium/src/+/8b9172a61f4e507b2eef30b2af438d2c19c0992d
memory:chrome:all_processes:reported_by_chrome:cc:effective_size: 2.067e+08 → 2.404e+08 (+3.368e+07)

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

Benchmark documentation link:
  https://bit.ly/system-health-benchmarks

Same justification as  https://crbug.com/897115 : the memory regression is expected because my CL effectively (and deliberately) negates some of the benefits of https://chromium-review.googlesource.com/c/chromium/src/+/1102025: some JPEG images need to be decoded to full size instead of a smaller size in order to avoid artifacts as described in  https://crbug.com/890745 .

To investigate this, I effectively reverted both:

- https://chromium-review.googlesource.com/c/chromium/src/+/1274845 (my CL)
- https://chromium-review.googlesource.com/c/chromium/src/+/1102025 (the earlier CL negated by mine)

Then, I ran a system_health.memory_desktop Pinpoint job using this revert for the bots and stories listed in https://chromeperf.appspot.com/group_report?bug_id=901390. The results for memory:chrome:all_processes:reported_by_chrome:cc:effective_size are:

Bot                              Story                                        Diff.
===================================================================================
Win 7 Perf                       multitab:misc:typical24:2018                 +0.0%

A positive % indicates a regression with respect to the revert, but the regression wasn't marked as significant.

Furthermore, with respect to the revert:

- For Win 7 Perf, the difference for memory:chrome:all_processes:reported_by_chrome:cc:effective_size is -2.2% which was marked as a significant improvement.

So, this suggests that at worst, my new CL simply takes us to the state before the CL that triggered the artifacts in  https://crbug.com/890745 .

There were other regressions, but none were large percentage-wise (the largest one was +9.8%), so I decided not to explore them further.

For reference:

CL with the reverts: https://chromium-review.googlesource.com/c/chromium/src/+/1305495
Win 7 Perf all results: https://pinpoint-dot-chromeperf.appspot.com/job/12a7d5ec140000
Win 7 Perf multitab:misc:typical24:2018 results: https://pinpoint-dot-chromeperf.appspot.com/job/14d7a8dc140000