Set user agent type of transient item the same as pending item.

ios/web/public/test/web_test_with_web_state.mm

Index: ios/web/public/test/web_test_with_web_state.mm
diff --git a/ios/web/public/test/web_test_with_web_state.mm b/ios/web/public/test/web_test_with_web_state.mm
index 9ee621e25276d62409c556f40ac4e203b2dc5f8d..963c6356fb79dcbcd319065f1905774c0f0c3b0f 100644
--- a/ios/web/public/test/web_test_with_web_state.mm
+++ b/ios/web/public/test/web_test_with_web_state.mm
@@ -7,6 +7,7 @@
 #include "base/run_loop.h"
 #include "base/strings/sys_string_conversions.h"
 #import "base/test/ios/wait_util.h"
+#import "ios/web/navigation/navigation_manager_impl.h"
 #include "ios/web/public/web_state/url_verification_constants.h"
 #include "ios/web/public/web_state/web_state_observer.h"
 #import "ios/web/web_state/ui/crw_web_controller.h"
@@ -42,6 +43,15 @@
   WebTest::TearDown();
 }
 
+void WebTestWithWebState::AddPendingItem(const GURL& url,
+                                         ui::PageTransition transition) {
+  GetWebController(web_state())
+      .webStateImpl->GetNavigationManagerImpl()
+      .AddPendingItem(url, Referrer(), transition,
+                      web::NavigationInitiationType::USER_INITIATED,
+                      web::NavigationManager::UserAgentOverrideOption::INHERIT);
+}
+
 void WebTestWithWebState::LoadHtml(NSString* html, const GURL& url) {
   // Sets MIME type to "text/html" once navigation is committed.
   class MimeTypeUpdater : public WebStateObserver {