[iOS] Refactoring web CRWSessionController user agent code.

ios/chrome/browser/tabs/tab_unittest.mm

Index: ios/chrome/browser/tabs/tab_unittest.mm
diff --git a/ios/chrome/browser/tabs/tab_unittest.mm b/ios/chrome/browser/tabs/tab_unittest.mm
index d863fa33d3bda575307b50090ba71e2ef0be14c3..cb6382b616f044abbaebde47441a52b860afd0dc 100644
--- a/ios/chrome/browser/tabs/tab_unittest.mm
+++ b/ios/chrome/browser/tabs/tab_unittest.mm
@@ -233,11 +233,8 @@ void BrowseTo(const GURL& userUrl, const GURL& redirectUrl, NSString* title) {
     web_state_impl_->OnProvisionalNavigationStarted(userUrl);
     [tab_ webWillAddPendingURL:redirectUrl
                     transition:ui::PAGE_TRANSITION_CLIENT_REDIRECT];
-    [[tab_ navigationManager]->GetSessionController()
-           addPendingItem:redirectUrl
-                 referrer:empty_referrer
-               transition:ui::PAGE_TRANSITION_CLIENT_REDIRECT
-        rendererInitiated:YES];
+    [tab_ navigationManager]->AddRendererInitiatedPendingItem(
+        redirectUrl, empty_referrer, ui::PAGE_TRANSITION_CLIENT_REDIRECT);
     web_state_impl_->OnProvisionalNavigationStarted(redirectUrl);
     [[tab_ navigationManager]->GetSessionController() commitPendingItem];
     [[tab_ webController] webStateImpl]->OnNavigationCommitted(redirectUrl);