Tested this issue on Mac 10.12.6 with chrome #60.0.3112.78,

Steps followed:
1. Downloaded provided zip
2. Navigated to index.htnl
3. Logged in with dummy credentials

Observations:
1. While submitting the credentials, chrome didn't ask for to save passwords.
2. While again logging into index.html, it didn't show the auto-suggestions for the username and password.

Attaching the screen-cast for reference.

viktor@ Could you please look into it and confirm that this issue you are facing? 

Thank You...

Deleted: 746593.mp4 873 KB

	746593.mp4 873 KB View Download

The recorded video _does not_ accurately show the issue. In order to see the issue this ticket is addressing please follow the steps:

1. download the attached archive polymer-forms-master.zip
2. unpack the archive into a folder named 'polymer-forms-master'
3. execute `npm install` in the polymer-forms-master folder
4. execute `npm start` in the polymer-forms-master folder
5. navigate to http://127.0.0.1:8000/#custom-in-shadow
--- OR (instead of the steps 1-5) ---
5. navigate to https://vlukashov.github.io/polymer-forms/#custom-in-shadow

6. fill-in the user name and password
7. click the 'Submit' button
8. see that the autofill did not work

The videos are already recorded and are available to download from https://github.com/vlukashov/polymer-forms/tree/master/videos. I'm now attaching two of them to ticket ticket:

How autofill is supposed to work (native form elements in the light DOM): chrome-native-in-light.mp4
How autofill actually does not work (custom elements in the shadow DOM): chrome-custom-in-shadow.mp4

Deleted: chrome-native-in-light.mp4 3.1 MB

	chrome-native-in-light.mp4 3.1 MB View Download

Deleted: chrome-custom-in-shadow.mp4 3.0 MB

	chrome-custom-in-shadow.mp4 3.0 MB View Download

Thank you for providing more feedback. Adding requester "kkaluri@chromium.org" to the cc list and removing "Needs-Feedback" label.

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

cc-ing some OWNERs of chrome/renderer/autofill/OWNERS.

I'm OOO until October. Adding the passwords component because this seems to also affect passwords autofill.

Bumping this to P1 because this is even broken for manual fallbacks of the password manager see https://vlukashov.github.io/polymer-forms/

Can Autofill folks work on this?

Investigating

 Issue 768573  has been merged into this issue.

 Issue 780422  has been merged into this issue.

+Keishi, I am wondering if you could possibly help with this issue?

+vasilii

I have this issue in my Polymer (v1) app.

I have been working on a work-around, but it doesn't completely replicate the issues I have in my (closed) app. It essentially adds event handlers to mirror the elements' values between the input elements inside Polymer elements (ie behind shadow roots) and input elements in the top level dom.

https://github.com/davidmaxwaterman/paper-input-password-manager

Using this technique in my actual app, if I save one set of credentials and then try to use a different set of credentials it seems to use the password for the first username.
It is also seems extraordinarily difficult to actually remove credentials from chrome's password manager. It seems almost never to forget. Perhaps this is something to do with the behaviour of the paper-input-container iron-input elements.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3fac6f366e575b9b60349af6b402fc140a44280d

commit 3fac6f366e575b9b60349af6b402fc140a44280d
Author: Kent Tamura <tkent@chromium.org>
Date: Fri Mar 02 10:39:46 2018

Add IsAutonomousCustomElement() and ShadowRoot() to blink::WebElement.

They are helpful for Autofill to traverse shadow trees of custom
elements.  This CL has no behavior changes because new functions are not
used yet.

Bug: 746593
Change-Id: I42249a47d122766bb7113c932e20c9cccacf5909
Reviewed-on: https://chromium-review.googlesource.com/945550
Reviewed-by: Takayoshi Kochi <kochi@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540488}
[modify] https://crrev.com/3fac6f366e575b9b60349af6b402fc140a44280d/third_party/WebKit/Source/core/exported/WebElement.cpp
[modify] https://crrev.com/3fac6f366e575b9b60349af6b402fc140a44280d/third_party/WebKit/Source/core/exported/WebElementTest.cpp
[modify] https://crrev.com/3fac6f366e575b9b60349af6b402fc140a44280d/third_party/WebKit/public/web/WebElement.h

FYI translate has similar problem regarding shadow DOM : issue 827339