Created web::UserAgentType.

ios/web/navigation/crw_session_controller.mm

Index: ios/web/navigation/crw_session_controller.mm
diff --git a/ios/web/navigation/crw_session_controller.mm b/ios/web/navigation/crw_session_controller.mm
index 7f7eec763044f42cc71f4adbadc558bfcb7f17de..56259b7fca54476d832a35c9549e98fa7ecd57d0 100644
--- a/ios/web/navigation/crw_session_controller.mm
+++ b/ios/web/navigation/crw_session_controller.mm
@@ -27,6 +27,7 @@
 #include "ios/web/public/browser_url_rewriter.h"
 #include "ios/web/public/referrer.h"
 #include "ios/web/public/ssl_status.h"
+#import "ios/web/public/web_client.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
@@ -507,8 +508,7 @@ - (void)pushNewItemWithURL:(const GURL&)URL
            initiationType:web::NavigationInitiationType::USER_INITIATED]);
 
   web::NavigationItemImpl* pushedItem = [pushedEntry navigationItemImpl];
-  pushedItem->SetIsOverridingUserAgent(
-      lastCommittedItem->IsOverridingUserAgent());
+  pushedItem->SetUserAgentType(lastCommittedItem->GetUserAgentType());
   pushedItem->SetSerializedStateObject(stateObject);
   pushedItem->SetIsCreatedFromPushState(true);
   pushedItem->GetSSL() = lastCommittedItem->GetSSL();
@@ -714,6 +714,8 @@ - (CRWSessionEntry*)sessionEntryWithURL:(const GURL&)url
   item->SetReferrer(referrer);
   item->SetTransitionType(transition);
   item->SetNavigationInitiationType(initiationType);
+  if (web::GetWebClient()->IsAppSpecificURL(loaded_url))
+    item->SetUserAgentType(web::UserAgentType::NONE);
   return [[CRWSessionEntry alloc] initWithNavigationItem:std::move(item)];
 }