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

ios/web/navigation/navigation_manager_impl.h

 // 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.
 
 #ifndef IOS_WEB_NAVIGATION_NAVIGATION_MANAGER_IMPL_H_
 #define IOS_WEB_NAVIGATION_NAVIGATION_MANAGER_IMPL_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 77 matching lines @@
   void OnNavigationItemCommitted();
 
   // Temporary accessors and content/ class pass-throughs.
   // TODO(stuartmorgan): Re-evaluate this list once the refactorings have
   // settled down.
   CRWSessionController* GetSessionController();
   void LoadURL(const GURL& url,
                const Referrer& referrer,
                ui::PageTransition type);
 
+  // Adds a transient item with the given URL. A transient item will be
+  // discarded on any navigation.
+  void AddTransientItem(const GURL& url);

[Eugene But (OOO till 7-30), 2017/03/30 23:01:49]

Please add tests for this new method

[liaoyuke, 2017/03/31 15:50:12]

Thank you for catching this!

+
   // Adds a new item with the given url, referrer, navigation type, and
   // initiation type, making it the pending item. If pending item is the same as
   // the current item, this does nothing. |referrer| may be nil if there isn't
   // one. The item starts out as pending, and will be lost unless
   // |-commitPendingItem| is called.
   void AddPendingItem(const GURL& url,
                       const web::Referrer& referrer,
                       ui::PageTransition navigation_type,
                       NavigationInitiationType initiation_type);
 
@@ skipping 84 matching lines @@
   // List of transient url rewriters added by |AddTransientURLRewriter()|.
   std::unique_ptr<std::vector<BrowserURLRewriter::URLRewriter>>
       transient_url_rewriters_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationManagerImpl);
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_NAVIGATION_NAVIGATION_MANAGER_IMPL_H_