Created web::UserAgentType.

ios/web/web_state/ui/crw_web_controller.mm

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/web/web_state/ui/crw_web_controller.h"
 
 #import <WebKit/WebKit.h>
 
 #import <objc/runtime.h>
 #include <stddef.h>
@@ skipping 2333 matching lines @@
   // the page has no navigation items, as occurs when an App Store link is
   // opened from another application.
   BOOL rendererInitiatedWithoutInteraction =
       self.sessionController.openedByDOM && !_userInteractedWithWebController;
   BOOL noNavigationItems = !(self.navigationManagerImpl->GetItemCount());
   return rendererInitiatedWithoutInteraction || noNavigationItems;
 }
 
 - (BOOL)usesDesktopUserAgent {
   web::NavigationItem* item = [self currentNavItem];
-  return item && item->IsOverridingUserAgent();
+  return item && item->GetUserAgentType() == web::UserAgentType::DESKTOP;
 }
 
 - (web::MojoFacade*)mojoFacade {
   if (!_mojoFacade) {
     service_manager::mojom::InterfaceProvider* interfaceProvider =
         _webStateImpl->GetMojoInterfaceRegistry();
     _mojoFacade.reset(new web::MojoFacade(interfaceProvider, self));
   }
   return _mojoFacade.get();
 }
@@ skipping 31 matching lines @@
                              fromEntry:fromEntry];
   [_delegate webWillFinishHistoryNavigationFromEntry:fromEntry];
 }
 
 - (void)updateDesktopUserAgentForEntry:(CRWSessionEntry*)entry
                              fromEntry:(CRWSessionEntry*)fromEntry {
   web::NavigationItemImpl* item = entry.navigationItemImpl;
   web::NavigationItemImpl* fromItem = fromEntry.navigationItemImpl;
   if (!item || !fromItem)
     return;
-  bool useDesktopUserAgent = item->IsOverridingUserAgent();
-  if (useDesktopUserAgent != fromItem->IsOverridingUserAgent()) {
+  if (item->GetUserAgentType() != fromItem->GetUserAgentType())

[Eugene But (OOO till 7-30), 2017/02/25 01:51:52]

If new UA is NONE, then page reconstruction is unnecessary, right?

[kkhorimoto, 2017/02/27 23:29:04]

Done.

     [self requirePageReconstruction];
-  }
 }
 
 #pragma mark -
 #pragma mark CRWWebControllerContainerViewDelegate
 
 - (CRWWebViewProxyImpl*)contentViewProxyForContainerView:
         (CRWWebControllerContainerView*)containerView {
   return _webViewProxy.get();
 }
 
@@ skipping 2828 matching lines @@
 - (void)simulateLoadRequestWithURL:(const GURL&)URL {
   _lastRegisteredRequestURL = URL;
   _loadPhase = web::LOAD_REQUESTED;
 }
 
 - (NSString*)referrerFromNavigationAction:(WKNavigationAction*)action {
   return [action.request valueForHTTPHeaderField:kReferrerHeaderName];
 }
 
 @end