All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=905197

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=7866c3157b8967e674940e29318942824d07d454fb1fd72b81d458c7cc882493


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

mac-10_12_laptop_low_end-perf

blink_perf.shadow_dom - Benchmark documentation link:
  https://bit.ly/blink-perf-benchmarks

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/1322e780140000

📍 Found significant differences after each of 2 commits.
https://pinpoint-dot-chromeperf.appspot.com/job/1322e780140000

Move GetFetchClientSettingsObject() to FetchContext by hiroshige@chromium.org
https://chromium.googlesource.com/chromium/src/+/cb193cc583121820faf4c42d3debb2aeb1e50754
v1-mutate-shallow-tree-then-slot-flatten: 20.05 → 20.32 (+0.2667)

Add assigned_nodes_index_ map for slot's assigned child by rakina@chromium.org
https://chromium.googlesource.com/chromium/src/+/eaddcb2899f1120b8a8d4d30d3c2a2911e65d049
v1-mutate-shallow-tree-then-slot-flatten: 20.41 → 27.07 (+6.659)

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

Benchmark documentation link:
  https://bit.ly/blink-perf-benchmarks

This can be a perf regression.