[iOS] Refactoring web CRWSessionController user agent code.

ios/web/navigation/navigation_manager_impl.h

Index: ios/web/navigation/navigation_manager_impl.h
diff --git a/ios/web/navigation/navigation_manager_impl.h b/ios/web/navigation/navigation_manager_impl.h
index cf1b29562b7eca3487604784d65e6a613354ca0e..64af61c84b7642b5437846f554dcc41148c07f30 100644
--- a/ios/web/navigation/navigation_manager_impl.h
+++ b/ios/web/navigation/navigation_manager_impl.h
@@ -82,6 +82,17 @@ class NavigationManagerImpl : public NavigationManager {
                const Referrer& referrer,
                ui::PageTransition type);
 
+  // Add a new item with the given url, referrer, and navigation type, making it
+  // the current 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.

[Eugene But (OOO till 7-30), 2017/02/16 02:20:48]

Please document the difference between UserInitiated and RendererInitiated

[liaoyuke, 2017/02/16 22:04:29]

Done.

+  void AddUserInitiatedPendingItem(const GURL& url,
+                                   const web::Referrer& referrer,
+                                   ui::PageTransition type);
+  void AddRendererInitiatedPendingItem(const GURL& url,
+                                       const web::Referrer& referrer,
+                                       ui::PageTransition type);
+
   // Convenience accessors to get the underlying NavigationItems from the
   // SessionEntries returned from |session_controller_|'s -lastUserEntry and
   // -previousEntry methods.
@@ -119,6 +130,7 @@ class NavigationManagerImpl : public NavigationManager {
   void GoForward() override;
   void GoToIndex(int index) override;
   void Reload(bool check_for_reposts) override;
+  void OverrideDesktopUserAgentForNextPendingItem() override;
 
   // Returns the current list of transient url rewriters, passing ownership to
   // the caller.
@@ -150,6 +162,21 @@ class NavigationManagerImpl : public NavigationManager {
   // |index| has ui::PAGE_TRANSITION_IS_REDIRECT_MASK.
   bool IsRedirectItemAtIndex(int index) const;
 
+  // Add a new item with the given url, referrer, and navigation type, making it
+  // the current 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 type,
+                      bool renderer_initiated);
+
+  // If true, override navigation item's useDesktopUserAgent flag and always
+  // create the pending entry using the desktop user agent.
+  // TODO(crbug.com/692303): Remove this when overriding the user agent doesn't
+  // create a new NavigationItem.
+  bool override_desktop_user_agent_for_next_pending_item_;
+
   // The primary delegate for this manager.
   NavigationManagerDelegate* delegate_;