Using the per-revision bisect providing the bisect results,
Good build:55.0.2886.0(Revision: 424099).
Bad build: 55.0.2887.0 (Revision:424315).

Observed in Chrome canary 55.0.2888.0 and also observed in Linux OS.

You are probably looking for a change made after 424126 (known good), but no later than 424127 (first known bad).

CHANGELOG URL:

The script might not always return single CL as suspectas some perf builds might get missing due to failure.
  
https://chromium.googlesource.com/chromium/src/+log/a15d8ad9e7947411da021d99dee97c7aae2b9358..911a4d605e2c485c0cc9547b084a9a3bd3c2e495

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

@finnur - Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Review-Url: https://codereview.chromium.org/2391253002

Thanks!

It is likely that my change affected it. Dave is the appropriate person to look into it, though.

Just a note in case someone else looks at this: My first guess is that the .secondary padding is pushing it up. This happened before and the css was modified to check whether the .secondary was :empty, that likely got broken or confused.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2

commit 3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2
Author: dschuyler <dschuyler@chromium.org>
Date: Thu Oct 20 18:22:48 2016

[MD settings] content settings add site button; layout fixes

This CL moves the 'Add site exception' button to an 'Add' button on the
header line of the site exceptions. The filter for the site data has
been moved into the list of sites. The remove all local cookie and
storage button has been removed from the list of cookies (it's still
available in the dialog).

Also, the misalignment of .secondary text in checkboxes and content
settings has been fixed.

BUG= 654875 ,  655036 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://chromiumcodereview.appspot.com/2429973003
Cr-Commit-Position: refs/heads/master@{#426536}

[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/app/settings_strings.grdp
[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/browser/resources/settings/controls/settings_checkbox.html
[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/browser/resources/settings/settings_shared_css.html
[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/browser/resources/settings/site_settings/site_data.html
[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/browser/resources/settings/site_settings/site_data.js
[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/browser/resources/settings/site_settings/site_list.html
[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/browser/resources/settings/site_settings/site_list.js
[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/browser/resources/settings/site_settings/site_settings_category.html
[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/browser/ui/webui/settings/md_settings_localized_strings_provider.cc
[modify] https://crrev.com/3d8adf8d41aee5f64a004bf89ec3c0cbaa7b4cb2/chrome/test/data/webui/settings/site_list_tests.js