The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d6704fdd14fd7b682858f14a36bfc5f9703922c8

commit d6704fdd14fd7b682858f14a36bfc5f9703922c8
Author: Danyao Wang <danyao@google.com>
Date: Fri Feb 16 02:31:13 2018

[Nav Experiment] Move ReloadWithUserAgentType into NavigationManager.

This is a code cleanup before changing ReloadWithUserAgentType() to work
also with WKBasedNavigationManager, which would not be appropriate to
add to tab.mm.

This CL also fixed an apparent bug where IsItemRedirectItem() in
tab.mm seemed to have always used the wrong polarity in detecting
redirect items.

Bug:  798836 
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Id39b3788a566fc8b188bdceb3a02803e5e182364
Reviewed-on: https://chromium-review.googlesource.com/920101
Commit-Queue: Danyao Wang <danyao@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537113}
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/chrome/browser/tabs/tab.mm
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/chrome/browser/web/BUILD.gn
[delete] https://crrev.com/b825a4218938f22c9e685dabfff64b0957d3e420/ios/chrome/browser/web/navigation_manager_util.h
[delete] https://crrev.com/b825a4218938f22c9e685dabfff64b0957d3e420/ios/chrome/browser/web/navigation_manager_util.mm
[delete] https://crrev.com/b825a4218938f22c9e685dabfff64b0957d3e420/ios/chrome/browser/web/navigation_manager_util_unittest.mm
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/web/navigation/legacy_navigation_manager_impl.h
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/web/navigation/legacy_navigation_manager_impl.mm
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/web/navigation/navigation_manager_impl.h
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/web/navigation/navigation_manager_impl.mm
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/web/navigation/navigation_manager_impl_unittest.mm
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/web/public/navigation_manager.h
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/web/public/test/fakes/test_navigation_manager.h
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/web/public/test/fakes/test_navigation_manager.mm
[modify] https://crrev.com/d6704fdd14fd7b682858f14a36bfc5f9703922c8/ios/web/web_state/navigation_and_load_callbacks_inttest.mm

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/24290122602dfb9c689bd044c23f6ee9d1ecf188

commit 24290122602dfb9c689bd044c23f6ee9d1ecf188
Author: Danyao Wang <danyao@google.com>
Date: Fri Feb 16 05:14:32 2018

[Nav Experiment] Fix Request Desktop Page for WKBasedNavigationManager.

With LegacyNavigationManager, Tab calls |requirePageReconstruction|
to free the WKWebView so that it'll be recreated with the user agent of
the newest navigation item. This approach doesn't work for
WKBasedNavigationManager because deleting the WKWebView would require
reconstruction of history.

Luckily with iOS9+, WKWebView.customUserAgent can be updated on an
existing WKWebView and will cause the new header to be sent to the
server. This CL uses this mechanism to update the UA before loading
a request based on the current NavigationItem.

This alone only reloads the visible page with the new UA under
WKBasedNavigationManager because there is no URL change. So to create
a back/forward entry, the URL is reloaded using restore_session.html
with a client-side redirect.

This CL fixes RequestDesktopMobileSiteTestCase for new nav manager.

Bug:  798836 
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I7f23232b10a7c83db16f545cd29445a514eaa57c
Reviewed-on: https://chromium-review.googlesource.com/919175
Commit-Queue: Danyao Wang <danyao@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537209}
[modify] https://crrev.com/24290122602dfb9c689bd044c23f6ee9d1ecf188/ios/web/navigation/BUILD.gn
[modify] https://crrev.com/24290122602dfb9c689bd044c23f6ee9d1ecf188/ios/web/navigation/navigation_manager_impl.mm
[modify] https://crrev.com/24290122602dfb9c689bd044c23f6ee9d1ecf188/ios/web/navigation/wk_based_restore_session_util.h
[modify] https://crrev.com/24290122602dfb9c689bd044c23f6ee9d1ecf188/ios/web/navigation/wk_based_restore_session_util.mm
[modify] https://crrev.com/24290122602dfb9c689bd044c23f6ee9d1ecf188/ios/web/navigation/wk_based_restore_session_util_unittest.mm
[modify] https://crrev.com/24290122602dfb9c689bd044c23f6ee9d1ecf188/ios/web/web_state/ui/crw_web_controller.mm