This is also the case in 59.0.3071.115, which is current mac stable. Do we know if this is a regression?

Dropping priority; this is not a regression, it's just ~always been busted. The color comes from ConstrainedWindowCustomWindow, which uses chrome_style::GetBackgroundColor() as its default background color, which is SK_ColorWHITE on Mac. I'm not sure if the collected cookies dialog is misusing ConstrainedWindowCustomWindow or if chrome_style::GetBackgroundColor() is returning the wrong thing on Mac.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/74b56fb13c1ebc11d1f2f08ec071379988a1a433

commit 74b56fb13c1ebc11d1f2f08ec071379988a1a433
Author: Elly Fong-Jones <ellyjones@chromium.org>
Date: Fri Jul 21 21:07:57 2017

cocoa: use cocoa background color for constrained windows

These were using SK_ColorWHITE when they should have been using
[NSColor windowBackgroundColor].

BUG= 743120 

Change-Id: Icf5cff4c1e4451c55580921c0d661fd8381b19da
Reviewed-on: https://chromium-review.googlesource.com/575167
Reviewed-by: Jayson Adams <shrike@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488748}
[modify] https://crrev.com/74b56fb13c1ebc11d1f2f08ec071379988a1a433/chrome/browser/ui/cocoa/chrome_style.cc
[modify] https://crrev.com/74b56fb13c1ebc11d1f2f08ec071379988a1a433/chrome/browser/ui/cocoa/chrome_style.h
[modify] https://crrev.com/74b56fb13c1ebc11d1f2f08ec071379988a1a433/chrome/browser/ui/cocoa/constrained_window/constrained_window_custom_window.mm

Except.. Cocoa buttons are white, but our constrained window buttons are not.

Now we have grey buttons on a grey background, which I think looks a little odd.

Deleted: Screen Shot 2017-07-26 at 19.18.07.png 728 KB

	Screen Shot 2017-07-26 at 19.18.07.png 728 KB View Download

(Note Safari is using a white background for this particular dialog, but it has different "buttons" again).

Deleted: Screen Shot 2017-07-26 at 20.06.37.png 303 KB

	Screen Shot 2017-07-26 at 20.06.37.png 303 KB View Download

Reverted https://chromium-review.googlesource.com/c/chromium/src/+/575167 as https://chromium-review.googlesource.com/c/chromium/src/+/744081 because it caused visual regressions in other dialogs. I will put up a more targeted fix for this.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/52211998d302b5097a83d1010d6ea786a3e6ad03

commit 52211998d302b5097a83d1010d6ea786a3e6ad03
Author: Elly Fong-Jones <ellyjones@chromium.org>
Date: Mon Oct 30 16:43:58 2017

Revert "cocoa: use cocoa background color for constrained windows"

This reverts commit 74b56fb13c1ebc11d1f2f08ec071379988a1a433.

Reason for revert:
This introduced other regressions, as documented on the linked bug.

Original change's description:
> cocoa: use cocoa background color for constrained windows
> 
> These were using SK_ColorWHITE when they should have been using
> [NSColor windowBackgroundColor].
> 
> BUG= 743120 
> 
> Change-Id: Icf5cff4c1e4451c55580921c0d661fd8381b19da
> Reviewed-on: https://chromium-review.googlesource.com/575167
> Reviewed-by: Jayson Adams <shrike@chromium.org>
> Reviewed-by: Mark Mentovai <mark@chromium.org>
> Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#488748}

TBR=ellyjones@chromium.org,shrike@chromium.org,mark@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug:  743120 
Change-Id: I9d86a973a55ff7cf6df39ae54ef7a5e602e680fb
Reviewed-on: https://chromium-review.googlesource.com/744081
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512510}
[modify] https://crrev.com/52211998d302b5097a83d1010d6ea786a3e6ad03/chrome/browser/ui/cocoa/chrome_style.cc
[modify] https://crrev.com/52211998d302b5097a83d1010d6ea786a3e6ad03/chrome/browser/ui/cocoa/chrome_style.h
[modify] https://crrev.com/52211998d302b5097a83d1010d6ea786a3e6ad03/chrome/browser/ui/cocoa/constrained_window/constrained_window_custom_window.mm

Can we just fix the collected cookies dialog and avoid touching the others?

ellyjones@ Tested this issue on Mac OS 10.12.6 using the latest Canary 64.0.3254.0 by following the steps mentioned in the original comment.
Attached is the screen cast of the issue after the fix was landed.

Can you please check and confirm if the fix is working as intended or no?

Thanks...

Deleted: 743120.webm 1.1 MB

	743120.webm 1.1 MB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2a3981b3710692cf94e6b5ded85cdc30370b2f47

commit 2a3981b3710692cf94e6b5ded85cdc30370b2f47
Author: Elly Fong-Jones <ellyjones@chromium.org>
Date: Tue Oct 31 14:22:25 2017

cocoa: use window background for collected cookies

This dialog looks odd with the default white background of a constrained
window.

Bug:  743120 
Change-Id: Id9870b246e8d46310870adef2a95ca4f5f4bd0a1
Reviewed-on: https://chromium-review.googlesource.com/746525
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512824}
[modify] https://crrev.com/2a3981b3710692cf94e6b5ded85cdc30370b2f47/chrome/browser/ui/cocoa/content_settings/collected_cookies_mac.mm

Fixed again but better :)

Verified this issue on Mac OS 10.12.6 using latest chrome build 64.0.3255.0 by following steps mentioned in the original comment.
Observed that the dialog is not having the white background in the latest version of Chrome.
Attaching screen-shot for reference. 
Hence adding TE-Verified labels.

Thanks..

Deleted: 743120.png 191 KB

	743120.png 191 KB View Download