NTP looks pretty bad, and this is reproduced even if you just focus on omnibox and then  hit cancel button.

Issue 918978 has been merged into this issue.

https://chromium-review.googlesource.com/c/chromium/src/+/1392956

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9e8283e92b17fab103fd5e6acd7e2c0ad8de5836

commit 9e8283e92b17fab103fd5e6acd7e2c0ad8de5836
Author: Gauthier Ambard <gambard@chromium.org>
Date: Fri Jan 04 14:01:26 2019

[iOS] Fix NTP frame

This CL fixes the frame computation for the NTP, taking into account
the BrowserContainerFullscreen experiment.

Bug:  918435 
Change-Id: I55e31b86262c3b30ae3a51029dba2336929076a5
Reviewed-on: https://chromium-review.googlesource.com/c/1392956
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619940}
[modify] https://crrev.com/9e8283e92b17fab103fd5e6acd7e2c0ad8de5836/ios/chrome/browser/ui/browser_view_controller.mm

Test, can we verify this is fixed now.

kariahda@

Issue is reproducible on latest M72 beta build

App version: 72.0.3626.51 beta
Devices: iPhone 7 Plus, iPhone XS Max
iOS Version: 12.1.2

Grey bar is seen on NTP 

Video:
https://drive.google.com/open?id=1QdkfjfRG3Yt_u0PfHKon-MlxqLT-IyWx

Note:

Issue is not reproducible on latest M73(73.0.3665.0) canary build

Ok, it seems if this is fixed on canary this should no longer block dev.

gambard/kkhorimoto: Should this be merged to M72?

Yes, the CL that caused this issue was merged to M72, so we should merge this as well.  Requesting merge and setting myself as owner.

This bug requires manual review: Less than 17 days to go before AppStore submit on M72
Please contact the milestone owner if you have questions.
Owners: govind@(Android), kariahda@(iOS), djmm@(ChromeOS), abdulsyed@(Desktop)

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

Approved. Thanks for taking the lead on this Kurt.

Another set of repro steps from TestFlight user:

-----
Grey bar at the top doesn't go away on new tab screen. STR:

1. Launch browser
2. Navigate to a page
3. Close using pull down and swipe shortcut
4. Open new tab page

Happens every time.
-----

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d12e3ef49b08907890a7126ecf4cc6005a334496

commit d12e3ef49b08907890a7126ecf4cc6005a334496
Author: Gauthier Ambard <gambard@chromium.org>
Date: Fri Jan 11 18:18:13 2019

[iOS] Fix NTP frame

This CL fixes the frame computation for the NTP, taking into account
the BrowserContainerFullscreen experiment.

Bug:  918435 
Change-Id: I55e31b86262c3b30ae3a51029dba2336929076a5
Reviewed-on: https://chromium-review.googlesource.com/c/1392956
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#619940}(cherry picked from commit 9e8283e92b17fab103fd5e6acd7e2c0ad8de5836)
Reviewed-on: https://chromium-review.googlesource.com/c/1407369
Reviewed-by: Kurt Horimoto <kkhorimoto@chromium.org>
Cr-Commit-Position: refs/branch-heads/3626@{#646}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}
[modify] https://crrev.com/d12e3ef49b08907890a7126ecf4cc6005a334496/ios/chrome/browser/ui/browser_view_controller.mm

The following revision refers to this bug: 
https://chromium.googlesource.com/chromium/src.git/+/d12e3ef49b08907890a7126ecf4cc6005a334496

Commit: d12e3ef49b08907890a7126ecf4cc6005a334496
Author: gambard@chromium.org
Commiter: kkhorimoto@chromium.org
Date: 2019-01-11 18:18:13 +0000 UTC

[iOS] Fix NTP frame

This CL fixes the frame computation for the NTP, taking into account
the BrowserContainerFullscreen experiment.

Bug:  918435 
Change-Id: I55e31b86262c3b30ae3a51029dba2336929076a5
Reviewed-on: https://chromium-review.googlesource.com/c/1392956
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#619940}(cherry picked from commit 9e8283e92b17fab103fd5e6acd7e2c0ad8de5836)
Reviewed-on: https://chromium-review.googlesource.com/c/1407369
Reviewed-by: Kurt Horimoto <kkhorimoto@chromium.org>
Cr-Commit-Position: refs/branch-heads/3626@{#646}
Cr-Branched-From: d897fb137fbaaa9355c0c93124cc048824eb1e65-refs/heads/master@{#612437}

This bug should be available to the public so TestFlight users who encountered this issue can follow the progress.

Verified the issue on chrome beta version 72.0.3626.59 on iPhone 8 plus with iOS 12.1.3 beta 4, iPhone X and iPhone XS max with iOS 12.1.2, following the steps mentioned in comment #0.  Grey bar on NTP is not displayed.  Looks good.