implement user agent override option.

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 1475 matching lines @@
   [_delegate webWillAddPendingURL:requestURL transition:transition];
   // Add or update pending url.
   if (self.navigationManagerImpl->GetPendingItem()) {
     // Update the existing pending entry.
     // Typically on PAGE_TRANSITION_CLIENT_REDIRECT.
     [[self sessionController] updatePendingItem:requestURL];
   } else {
     // A new session history entry needs to be created.
     self.navigationManagerImpl->AddPendingItem(
         requestURL, referrer, transition,
-        web::NavigationInitiationType::RENDERER_INITIATED);
+        web::NavigationInitiationType::RENDERER_INITIATED,
+        web::NavigationManager::UserAgentOverrideOption::INHERIT);
   }
   _webStateImpl->SetIsLoading(true);
   _webStateImpl->OnProvisionalNavigationStarted(requestURL);
 }
 
 - (void)updateHTML5HistoryState {
   web::NavigationItemImpl* currentItem = self.currentNavItem;
   if (!currentItem)
     return;
 
@@ skipping 305 matching lines @@
   [self recordStateInHistory];
 
   if (!self.currentNavItem)
     initialNavigation = YES;
 
   web::NavigationInitiationType navigationInitiationType =
       params.is_renderer_initiated
           ? web::NavigationInitiationType::RENDERER_INITIATED
           : web::NavigationInitiationType::USER_INITIATED;
   self.navigationManagerImpl->AddPendingItem(
-      navUrl, params.referrer, transition, navigationInitiationType);
+      navUrl, params.referrer, transition, navigationInitiationType,
+      params.user_agent_override_option);
 
   web::NavigationItemImpl* addedItem = self.currentNavItem;
   DCHECK(addedItem);
   if (params.extra_headers)
     addedItem->AddHttpRequestHeaders(params.extra_headers);
   if (params.post_data) {
     DCHECK([addedItem->GetHttpRequestHeaders() objectForKey:@"Content-Type"])
         << "Post data should have an associated content type";
     addedItem->SetPostData(params.post_data);
     addedItem->SetShouldSkipRepostFormConfirmation(true);
@@ skipping 3243 matching lines @@
 - (void)simulateLoadRequestWithURL:(const GURL&)URL {
   _lastRegisteredRequestURL = URL;
   _loadPhase = web::LOAD_REQUESTED;
 }
 
 - (NSString*)referrerFromNavigationAction:(WKNavigationAction*)action {
   return [action.request valueForHTTPHeaderField:kReferrerHeaderName];
 }
 
 @end