Using the per-revision bisect providing the bisect results,
Good build: 54.0.2839.0 (Revision: 414243).
Bad build: 54.0.2840.0 (Revision: 414607).

You are probably looking for a change made after 414245 (known good), but no later than 414246 (first known bad).

CHANGE-LOG URL:
---------------
https://chromium.googlesource.com/chromium/src/+log/449e2fc928a4a579182f6f49f4defbfcec2b1c4c..9a670d48822912050a3c06bf1f3afb1a01c1e0a3

From the CL above, assigning the issue to the concern owner

@michaelpg : Could you please look into the issue, pardon me if it has nothing to do with your changes and if possible please assign it to concern owner.

Review-Url: https://codereview.chromium.org/2265253002
Note :Able to reproduce the issue in Ubuntu 14.04,Win 10.0 and Mac 10.12.3 and Able to reproduce in latest Canary #58.0.3027.0

gah, more iron-list bugs. dbeam@ can you triage -- is this something we've seen before? if not, someone still working on Settings who's familiar with iron-list and/or dialogs should probably take a look.

It's possible this is triggered by the focus() behavior in add_languages_dialog.js, but that wouldn't match the regression range.

https://cs.chromium.org/chromium/src/chrome/browser/resources/settings/languages_page/add_languages_dialog.js?type=cs&q=focus+file:language+file:settings&sq=package:chromium&l=54

From initial triaging, there's only a few languages checkboxes that does this. I found so far "Chinese (Simplified)", "Hungarian", "French" would do this. 

Pretty sure this odd behavior is related: If you scroll to somewhere near one of these languages and check another language, you'll notice a quick blink of a focus ripple around the checkbox of one of the aforementioned language.

For example: Open the add language dialog, scroll down such that both "Chinese" and "Chinese (simplified)" are visible. Check the "Chinese" checkbox while staring at the "Chinese (simplified)" checkbox, and you'll see a flash of ripple around the "Chinese (simplified)" checkbox.

My first guess is how iron-list lazily load the items - will keep triaging.

It looks like the problem is most likely related to how iron-list lazily loads 20 items at a time - it seems like the problematic check-boxes are always the last of them 20-item batch in the dom. 

Also just noticed that the "tap" event doesn't even trigger for the element on first interaction, so it smells like the element's not added into the DOM correctly somehow.

For more context, the aforementioned languages that have issues is under the assumption that "English" and "English (United States)" are your only added languages. Otherwise, you might see issues with a whole different subset.

Was able to reproduce the issue with minimal repro step in a fiddle:
https://jsfiddle.net/cyenptb4/7/

and have filed an issue here: https://github.com/PolymerElements/iron-list/issues/411

The pattern seems to be consistent with my previous guess that every first item of the lazily loaded batch displays this problematic behavior.

I haven't found which part of the code is causing this issue, nor a workaround yet. Will keep looking into it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/262914424bb02c970d5593c9f66d8f2657d022ff

commit 262914424bb02c970d5593c9f66d8f2657d022ff
Author: dbeam <dbeam@chromium.org>
Date: Thu Mar 16 04:04:29 2017

Closure: remove pending_compiler_externs.js

The only thing they provided is already inside of compiler.jar's
externs.zip/browser/html5.js at this point (HTMLImportElement#import).

R=tbreisacher@chromium.org
BUG= 697353 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2754733002
Cr-Commit-Position: refs/heads/master@{#457345}

[modify] https://crrev.com/262914424bb02c970d5593c9f66d8f2657d022ff/third_party/closure_compiler/externs/compiled_resources2.gyp
[delete] https://crrev.com/880b3a975ba7d0a4eda16332bcb8bac63f561405/third_party/closure_compiler/externs/pending_compiler_externs.js
[modify] https://crrev.com/262914424bb02c970d5593c9f66d8f2657d022ff/third_party/closure_compiler/tools/create_include_gyp.py
[modify] https://crrev.com/262914424bb02c970d5593c9f66d8f2657d022ff/ui/webui/resources/js/compiled_resources.gyp
[modify] https://crrev.com/262914424bb02c970d5593c9f66d8f2657d022ff/ui/webui/resources/js/compiled_resources2.gyp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9e099d4c84b02fe2a6ee52883090a974ceb8cfd1

commit 9e099d4c84b02fe2a6ee52883090a974ceb8cfd1
Author: scottchen <scottchen@chromium.org>
Date: Thu Mar 16 08:49:04 2017

MD Settings: bump iron-list version.

Primarily to address an issue we're seeing in Settings where initial clicks
on certain row items aren't being registered.

BUG= 697353 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2751523005
Cr-Commit-Position: refs/heads/master@{#457373}

[modify] https://crrev.com/9e099d4c84b02fe2a6ee52883090a974ceb8cfd1/third_party/polymer/v1_0/bower.json
[modify] https://crrev.com/9e099d4c84b02fe2a6ee52883090a974ceb8cfd1/third_party/polymer/v1_0/components-chromium/iron-list/bower.json
[modify] https://crrev.com/9e099d4c84b02fe2a6ee52883090a974ceb8cfd1/third_party/polymer/v1_0/components-chromium/iron-list/iron-list-extracted.js
[modify] https://crrev.com/9e099d4c84b02fe2a6ee52883090a974ceb8cfd1/third_party/polymer/v1_0/components-chromium/iron-list/iron-list.html
[modify] https://crrev.com/9e099d4c84b02fe2a6ee52883090a974ceb8cfd1/third_party/polymer/v1_0/components_summary.txt