The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/591031b8ef75c36cb929d1e3e1ef401fcaaf799a

commit 591031b8ef75c36cb929d1e3e1ef401fcaaf799a
Author: Mark Cogan <marq@google.com>
Date: Mon Sep 17 17:39:32 2018

[iOS] Remove UI refresh flags and related code.

This CL removes the UI refresh flags and references to them. Specifically:

- The ui-refresh-phase-1, infobars-ui-reboot, and ui-refresh-location-bar about-flags are removed.
- The kRefreshPopupPresentation, kUIRefreshLocationBar, kInfobarsUIReboot and kInfobarsUIReboot feature flags are removed.
- IsRecentTabsUIRebootEnabled(), IsBookmarksUIRebootEnabled(), IsReadingListUIRebootEnabled(), IsSettingsUIRebootEnabled(), IsRefreshInfobarEnabled(), IsRefreshLocationBarEnabled(), IsRefreshPopupPresentationEnabled() and IsUIRefreshPhase1Enabled() are all updated to return |true|. (Note also that these functions are spread across two files; if we weren't going to delete them all ASAP, I'd move them together for consistency).
- ios_chrome_field_trails.cc is deleted and the methods are defined to be stubs.
- Unit tests that disabled kUIRefreshPhase1 via scopedFeatureList are removed. In the case of history_collection_view_controller_unittest, that meant deleting all of the file.
- Unit tests that enabled kUIRefreshPhase1 via scopedFeatureList have the scopedFeatureList removed.
- Unit tests that were named 'UIRefresh' (or similar) to distinguish them from now-deleted tests are renamed.

Bug:  884732 
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: Ib8bef563cb9a22e36bfe2482f930134d652347a2
Reviewed-on: https://chromium-review.googlesource.com/1228121
Commit-Queue: Mark Cogan <marq@chromium.org>
Reviewed-by: Peter Lee <pkl@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591727}
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/about_flags.mm
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/experimental_flags.h
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/experimental_flags.mm
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ios_chrome_field_trials.cc
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ios_chrome_flag_descriptions.cc
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ios_chrome_flag_descriptions.h
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/activity_services/activity_service_controller_unittest.mm
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/authentication/signin_promo_view_unittest.mm
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/bookmarks/cells/bookmark_parent_folder_item_unittest.mm
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/bookmarks/cells/bookmark_text_field_item_unittest.mm
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/fullscreen/fullscreen_web_state_observer_unittest.mm
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/history/BUILD.gn
[delete] https://crrev.com/806192f715b9beaacbfb121698bb5a58e747c514/ios/chrome/browser/ui/history/history_collection_view_controller_unittest.mm
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/ui_feature_flags.cc
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/ui_feature_flags.h
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/ui_util.h
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/browser/ui/ui_util.mm
[modify] https://crrev.com/591031b8ef75c36cb929d1e3e1ef401fcaaf799a/ios/chrome/test/earl_grey/chrome_matchers.h

Verified the issue on the build 71.0.3561.0 canary tested on (iPad iOS 11.4.1) and iPhone7+(iOS 12). 

UI Refresh flag hsa been removed from chrome://flags