All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=880899

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=035bdcc62ae4c4153f9b9cc705d2d29714295c267673e06b942cfae61508ed5d


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

Android Nexus5X WebView Perf

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

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/167e99b3640000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/167e99b3640000

Revert "Don't promote position: fixed elements with composited descendants if they don't scroll" by smcgruer@chromium.org
https://chromium.googlesource.com/chromium/src/+/365973dba9c887bb8cfd8b0d1edba41166fb094b
2.238e+07 → 2.351e+07 (+1.135e+06)

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

The memory regression was caused by the revert of a change which introduced a bug in WebView full-screen scrolling (see  issue 863361 ). As such, marking this WontFix.