Same thing with search.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ea473f6717656b6331c9afcec59972ee0a9439fd

commit ea473f6717656b6331c9afcec59972ee0a9439fd
Author: Elodie Banel <lod@google.com>
Date: Fri Sep 08 09:59:16 2017

Delay setting web toolbar controller trailing view hidden state.

When leaving the app in the focused omnibox state and reopening using
the search widget's new search button, the omnibox is closed due to
closing all modal views in the startup sequence, and then re-opened.
Setting the view hidden occurs in the completion block of the animation
which, due to the animation's duration, occurs after setting it back to
visible when re-opening the omnibox. This changes makes it so that the
hidden setting occur in the right order, leaving the view in a correct
final state. However, it does not solve the fact that the omnibox is
hidden then re-opened, which still leads to flickering.

Bug:  754119 
Change-Id: I95c785adfdca5ff214b010031b24fde4c475e70e
Reviewed-on: https://chromium-review.googlesource.com/654999
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Elodie Banel <lod@chromium.org>
Cr-Commit-Position: refs/heads/master@{#500554}
[modify] https://crrev.com/ea473f6717656b6331c9afcec59972ee0a9439fd/ios/chrome/browser/ui/toolbar/web_toolbar_controller.mm

The disappearing cancel button should be fixed by the previous CL, however this doesn't fix the flicker. Doing so will require modifying the startup function which closes all modals, including a focused omnibox prior to any analysis of startup parameters.

Hi,

This is marked P1 for M62. Please provide updates with the fix plan or blockers.

Thanks,

CL out to fix it via passing a parameter around. https://chromium-review.googlesource.com/c/chromium/src/+/687774 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/aa5ab43f3be953fd669336335bf977e1235bcce5

commit aa5ab43f3be953fd669336335bf977e1235bcce5
Author: Elodie Banel <lod@google.com>
Date: Thu Sep 28 14:42:01 2017

Keep omnibox visible on startup depending on startup params.

The omnibox is hidden when launching the app, but shown again if the
startup params are set to focus omnibox. This causes a visual flicker.
Passing around this argument makes it possible to not hide the omnibox
in the first place if it will be focused.

Bug:  754119 
Change-Id: I4a4e4f759c2be2bbdaa028ec7c34e49745848189
Reviewed-on: https://chromium-review.googlesource.com/687774
Commit-Queue: Elodie Banel <lod@chromium.org>
Reviewed-by: Rohit Rao (ping after 24h) <rohitrao@chromium.org>
Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505019}
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/app/application_delegate/mock_tab_opener.mm
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/app/application_delegate/tab_opening.h
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/app/application_delegate/url_opener.mm
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/app/application_delegate/user_activity_handler.mm
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/app/main_controller.mm
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/app/main_controller_private.h
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/browser/ui/browser_view_controller.h
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/browser/ui/browser_view_controller.mm
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/browser/ui/browser_view_controller_unittest.mm
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/browser/ui/toolbar/web_toolbar_controller.mm
[modify] https://crrev.com/aa5ab43f3be953fd669336335bf977e1235bcce5/ios/chrome/test/app/chrome_test_util.mm

 Issue 749030  has been merged into this issue.

Requesting merge for https://chromium-review.googlesource.com/687774

This bug requires manual review: Less than 11 days to go before AppStore submit on M62
Please contact the milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), bhthompson@(ChromeOS), abdulsyed@(Desktop)

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

Verified on 63.0.3231.0 Canary on iPhone6+ iOS 11.0, iPhone7+ iOS 10.3.3, iPad Pro 12'5 iOS 10.3.3.Flickering on the top bar in incognito tab when navigated back from quick actions is no longer seen.

BUT  Issue 749030  is still reproducible.I have assigned back that bug. Thanks.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ee5e63a83581789ba33788df196e5b938254c2af

commit ee5e63a83581789ba33788df196e5b938254c2af
Author: Elodie Banel <lod@google.com>
Date: Thu Oct 05 09:11:35 2017

Keep omnibox visible on startup depending on startup params.

The omnibox is hidden when launching the app, but shown again if the
startup params are set to focus omnibox. This causes a visual flicker.
Passing around this argument makes it possible to not hide the omnibox
in the first place if it will be focused.

Bug:  754119 
Change-Id: I4a4e4f759c2be2bbdaa028ec7c34e49745848189
Reviewed-on: https://chromium-review.googlesource.com/687774
Commit-Queue: Elodie Banel <lod@chromium.org>
Reviewed-by: Rohit Rao (ping after 24h) <rohitrao@chromium.org>
Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#505019}(cherry picked from commit aa5ab43f3be953fd669336335bf977e1235bcce5)
Reviewed-on: https://chromium-review.googlesource.com/701757
Reviewed-by: Elodie Banel <lod@chromium.org>
Cr-Commit-Position: refs/branch-heads/3202@{#589}
Cr-Branched-From: fa6a5d87adff761bc16afc5498c3f5944c1daa68-refs/heads/master@{#499098}
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/app/application_delegate/mock_tab_opener.mm
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/app/application_delegate/tab_opening.h
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/app/application_delegate/url_opener.mm
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/app/application_delegate/user_activity_handler.mm
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/app/main_controller.mm
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/app/main_controller_private.h
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/browser/ui/browser_view_controller.h
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/browser/ui/browser_view_controller.mm
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/browser/ui/browser_view_controller_unittest.mm
[modify] https://crrev.com/ee5e63a83581789ba33788df196e5b938254c2af/ios/chrome/test/app/chrome_test_util.mm

Verified the issue on 62.0.3202.52 beta tested on iPhone7+(11.0.1).
Flickering is not seen on opening a new incognito tab from today view