All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=871387

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=eb114f326c4fae40d9585a389e2543bff6af46705fbcd072e637e56dfc45b68c


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

android-nexus5x-perf

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/16e75ad0640000

📍 Found significant differences after each of 3 commits.
https://pinpoint-dot-chromeperf.appspot.com/job/16e75ad0640000

Enable use-zoom-for-dsf on Android on M70 by eirage@chromium.org
https://chromium.googlesource.com/chromium/src/+/d0b8bbd2dbf9c06dcbbd01a4b1285cf7a1bc2ba0
228 → 0.1074 (-227.9)

renderer: Remove dead code. by sadrul@chromium.org
https://chromium.googlesource.com/chromium/src/+/4e0335cf6ce255cf27eb33a25d1f4c21458343de
0.1069 → 0.1115 (+0.004618)

Use CompletionOnceCallback in DnsTransaction. by bnc@chromium.org
https://chromium.googlesource.com/chromium/src/+/cd2b196ca8c34712814a8b0bae32f60770e50cde
0.1113 → 0.1068 (-0.004501)

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

investigating..

This issue is also reproduced on desktop when we have not integer zoom factor.

Open http://output.jsbin.com/gacugir/15, this a mini version of the perf test page, ctrl +/- to zoom, click to trigger layout. 

when the zoom factor is not integer, it took way longer to layout than integer zoom factor.

I believe this issue is related to table doesn't support subpixels.
(It's not repro with simple divs: http://jsbin.com/domiyey)

 Issue 871405  has been merged into this issue.

Removing the blocking since this is also repro on desktop.

Update the summary and labels. 
unassign myself so someone from layout team can pick it up :)
(I believe the layout running slow is because the SetNeedsLayout here: https://cs.chromium.org/chromium/src/third_party/blink/renderer/core/layout/layout_table_cell.cc?type=cs&g=0&l=283)