I think the leading icon should fade in late in the animation, and the clear button should appear, if necessary, after the focus happens.

Uploaded https://chromium-review.googlesource.com/c/chromium/src/+/1152919

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cdf8699e0ced7796f3ab30afe6111bcd61c796de

commit cdf8699e0ced7796f3ab30afe6111bcd61c796de
Author: stkhapugin@chromium.org <stkhapugin@chromium.org>
Date: Wed Aug 01 11:44:49 2018

[iOS] Improvements of the focusing animation.

Fades the leading icon and the clear button to avoid overlapping with
the toolbar elements.

Bug:  867406 
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: Ib60719fe1adee84032bbd59588609fd63cfa06ed
Reviewed-on: https://chromium-review.googlesource.com/1152919
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579767}
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/location_bar/location_bar_coordinator.mm
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/location_bar/location_bar_generic_coordinator.h
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/omnibox/omnibox_container_view.h
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/omnibox/omnibox_container_view.mm
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/omnibox/omnibox_coordinator.h
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/omnibox/omnibox_coordinator.mm
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/omnibox/omnibox_view_controller.h
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/omnibox/omnibox_view_controller.mm
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/orchestrator/BUILD.gn
[add] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/orchestrator/edit_view_animatee.h
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/orchestrator/omnibox_focus_orchestrator.h
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/orchestrator/omnibox_focus_orchestrator.mm
[modify] https://crrev.com/cdf8699e0ced7796f3ab30afe6111bcd61c796de/ios/chrome/browser/ui/toolbar/adaptive/primary_toolbar_coordinator.mm

looking good on canary

This bug requires manual review: Less than 25 days to go before AppStore submit on M69
Please contact the milestone owner if you have questions.
Owners: amineer@(Android), kariahda@(iOS), cindyb@(ChromeOS), govind@(Desktop)

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

Approved. Please merge asap.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f72934db7d178c2ecb1607c2a6435100f0f3039b

commit f72934db7d178c2ecb1607c2a6435100f0f3039b
Author: stkhapugin@chromium.org <stkhapugin@chromium.org>
Date: Mon Aug 06 14:17:45 2018

[iOS] Improvements of the focusing animation.

Fades the leading icon and the clear button to avoid overlapping with
the toolbar elements.

Bug:  867406 
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: Ib60719fe1adee84032bbd59588609fd63cfa06ed
Reviewed-on: https://chromium-review.googlesource.com/1152919
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#579767}(cherry picked from commit cdf8699e0ced7796f3ab30afe6111bcd61c796de)
Reviewed-on: https://chromium-review.googlesource.com/1163683
Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/branch-heads/3497@{#415}
Cr-Branched-From: 271eaf50594eb818c9295dc78d364aea18c82ea8-refs/heads/master@{#576753}
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/location_bar/location_bar_coordinator.mm
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/location_bar/location_bar_generic_coordinator.h
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/omnibox/omnibox_container_view.h
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/omnibox/omnibox_container_view.mm
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/omnibox/omnibox_coordinator.h
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/omnibox/omnibox_coordinator.mm
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/omnibox/omnibox_view_controller.h
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/omnibox/omnibox_view_controller.mm
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/orchestrator/BUILD.gn
[add] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/orchestrator/edit_view_animatee.h
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/orchestrator/omnibox_focus_orchestrator.h
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/orchestrator/omnibox_focus_orchestrator.mm
[modify] https://crrev.com/f72934db7d178c2ecb1607c2a6435100f0f3039b/ios/chrome/browser/ui/toolbar/adaptive/primary_toolbar_coordinator.mm

Verified on M69.0.3497.31 beta
iOS: 12.0 beta#6
iPad Pro.

Omnibox Focus and defocus animation is looking good.