Issue is reproducible on the latest canary(58.0.3024.0) of Mac OS 10.12.3 as well.

Using the per-revision bisect providing the bisect results,
Good build: 58.0.3022.0 (Revision: 452713).
Bad build: 58.0.3023.0 (Revision: 453044).

You are probably looking for a change made after 452933 (known good), but no later than 453001 (first known bad).

CHANGE-LOG URL:
---------------
https://chromium.googlesource.com/chromium/src/+log/c1b9731d28d5fbf0dc02bc49665f4f38d5a26fac..d06eabc40101635e329c9e27e5008b123fdd815a

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

@ dbeam : 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/2700063002
Note :Able to reproduce the issue in Ubuntu 14.04,Win 10.0 and Mac 10.12.2. and Able to reproduce in latest Canary #58.0.3024.0

 Issue 696476  has been merged into this issue.

Adding Stable blocker as this is recent regression and seen across various textfields. 

AT = assistive technologies

I don't think ReleaseBlock-Stable is justified since MD Settings has not launched to stable yet. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b77998f76c35f41c8d4c590b468d893ecb00e191

commit b77998f76c35f41c8d4c590b468d893ecb00e191
Author: dpapad <dpapad@chromium.org>
Date: Wed Mar 01 18:08:40 2017

MD Settings: Autofocus first text input in various dialogs.

BUG= 696409 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2722873002
Cr-Commit-Position: refs/heads/master@{#453973}

[modify] https://crrev.com/b77998f76c35f41c8d4c590b468d893ecb00e191/chrome/browser/resources/settings/on_startup_page/startup_url_dialog.html
[modify] https://crrev.com/b77998f76c35f41c8d4c590b468d893ecb00e191/chrome/browser/resources/settings/passwords_and_forms_page/address_edit_dialog.html
[modify] https://crrev.com/b77998f76c35f41c8d4c590b468d893ecb00e191/chrome/browser/resources/settings/passwords_and_forms_page/credit_card_edit_dialog.html
[modify] https://crrev.com/b77998f76c35f41c8d4c590b468d893ecb00e191/chrome/browser/resources/settings/search_engines_page/search_engine_dialog.html
[modify] https://crrev.com/b77998f76c35f41c8d4c590b468d893ecb00e191/chrome/browser/resources/settings/site_settings/add_site_dialog.html
[modify] https://crrev.com/b77998f76c35f41c8d4c590b468d893ecb00e191/chrome/browser/resources/settings/site_settings/edit_exception_dialog.html

I am not actively working on this, so marking as available. I did update a few dialogs at r453973, but there is more (especially for ChromeOS).

i think the general experience here is not bad

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

I am closing this bug. Most dialogs I tried across Chrome and CrOS Settings seem to focus something useful (mostly looked at dilaogs with text inputs). We should file individual bugs for any dialog that needs fixing.