i will take this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fba466b8e35478b81b36ca09d7c23bbd80af8425

commit fba466b8e35478b81b36ca09d7c23bbd80af8425
Author: Hwanseung Lee <hs1217.lee@samsung.com>
Date: Mon May 14 05:06:07 2018

[WebUI] Toast button shuld not have hairline

the button in toasts of Bookmarks should not have a border.

Bug:  842013 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I2d431ba60b598125730eaf56b618fe3e9b1d9ccd
Reviewed-on: https://chromium-review.googlesource.com/1055132
Commit-Queue: Hwanseung Lee <hwanseung@chromium.org>
Reviewed-by: calamity <calamity@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558200}
[modify] https://crrev.com/fba466b8e35478b81b36ca09d7c23bbd80af8425/chrome/browser/resources/md_bookmarks/toast_manager.html

Able to reproduce the issue on chrome version 68.0.3430.0(build without fix)
Verified the fix on Mac 10.13.3 and Ubuntu 14.04 using Chrome version #68.0.3431.0 as per the comment #0.
Attaching screenshot for reference.
Observed that ""the button in toasts of Bookmarks not having a border.""
Hence, the fix is working as expected. 

Note: Unable to verify the fix on Windows 32 & 64 due to issue: 843012.

Thanks...!

Deleted: 842013.mp4 441 KB

	842013.mp4 441 KB View Download

This still happens in chrome://settings, see attached screenshot. Re-opening.

Deleted: toast_button.png 6.2 KB

	toast_button.png 6.2 KB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0aa07b3c9974c6f4169d7fd5ce227725e2a26497

commit 0aa07b3c9974c6f4169d7fd5ce227725e2a26497
Author: Esmael El-Moslimany <aee@chromium.org>
Date: Wed May 23 23:50:22 2018

Settings: removing border for buttons in cr-toast

Bug:  842013 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I0a3eb6e2343fc224da22a88cb1cc10581e6833c5
Reviewed-on: https://chromium-review.googlesource.com/1067766
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Esmael El-Moslimany <aee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561313}
[modify] https://crrev.com/0aa07b3c9974c6f4169d7fd5ce227725e2a26497/chrome/browser/resources/md_bookmarks/toast_manager.html
[modify] https://crrev.com/0aa07b3c9974c6f4169d7fd5ce227725e2a26497/chrome/browser/resources/settings/passwords_and_forms_page/passwords_section.html
[modify] https://crrev.com/0aa07b3c9974c6f4169d7fd5ce227725e2a26497/chrome/browser/resources/settings/people_page/sync_page.html
[modify] https://crrev.com/0aa07b3c9974c6f4169d7fd5ce227725e2a26497/ui/webui/resources/cr_elements/cr_toast/cr_toast.html

Able to reproduce the issue on chrome version 68.0.3435.0(build without fix)
Verified the fix on Windows 10,Mac 10.13.3 and Ubuntu 14.04 using Chrome version #68.0.3439.0 as per the comment #11.
Attaching screencast for reference.
Observed that "the button in toasts of Settings not having a border."
Adding verified labels as fix is working as expected. 

Thanks...!

Deleted: 842013.mp4 2.1 MB

	842013.mp4 2.1 MB View Download