Remove usage of Tab's |url| property from TabModel.

ios/web/navigation/navigation_manager_impl.mm

 // Copyright 2013 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/navigation/navigation_manager_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 194 matching lines @@
              last_non_native_item->GetUserAgentType() != UserAgentType::NONE);
       if (last_non_native_item) {
         pending_item->SetUserAgentType(
             last_non_native_item->GetUserAgentType());
       }
       break;
     }
   }
 }
 
+void NavigationManagerImpl::CommitPendingItem() {
+  [session_controller_ commitPendingItem];
+}
+
 BrowserState* NavigationManagerImpl::GetBrowserState() const {
   return browser_state_;
 }
 
 WebState* NavigationManagerImpl::GetWebState() const {
   return delegate_->GetWebState();
 }
 
 NavigationItem* NavigationManagerImpl::GetVisibleItem() const {
   return [session_controller_ visibleItem];
@@ skipping 214 matching lines @@
   const ScopedNavigationItemImplList& items = [session_controller_ items];
   while (index >= 0) {
     NavigationItem* item = items[index--].get();
     if (!client->IsAppSpecificURL(item->GetVirtualURL()))
       return item;
   }
   return nullptr;
 }
 
 }  // namespace web