[iOS] Refactoring web CRWSessionController user agent code.

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>
 #include <vector>
 
 #import "base/mac/scoped_nsobject.h"
 #include "base/macros.h"
 #import "ios/web/public/navigation_manager.h"
 #include "ui/base/page_transition_types.h"
 #include "url/gurl.h"
 
 @class CRWSessionController;
 
 namespace web {
 class BrowserState;
 class NavigationItem;
 struct Referrer;
 class NavigationManagerDelegate;
 class NavigationManagerFacadeDelegate;
 class SessionStorageBuilder;
 
+// |USER_INITIATED| represents pending item that is initiated by actual user

[Eugene But (OOO till 7-30), 2017/02/17 00:00:23]

Please move comment for enum values and place them before enum values and write
a comments to describe the enum itself (f.e. where it is used).

// Navigation was initiated by actual user action.
USER_INITIATED = 1,

// Navigation was initiated by renderer. Examples of renderer-initiated
navigations include:
//  * <a> link click
//  * changing window.location.href
//  * redirect via the <meta http-equiv="refresh"> tag
//  * using window.history.pushState
RENDERER_INITIATED

Please note that RENDERER_INITIATED is not the same as redirect and there is no
need to initialize second item (it is only needed when enum is used in UMA or
serialization and values should be stable).

[liaoyuke, 2017/02/17 01:16:51]

Thank you for the detailed explanation!

[Eugene But (OOO till 7-30), 2017/02/17 01:21:11]

Per my previous comment, please add comments for enum itself and remove  |= 2|

[liaoyuke, 2017/02/17 01:32:59]

Done.

+// actions, while |RENDERER_INITIATED| stands for pending item that is initiated
+// by Url redirect from another navigation item.
+enum class ItemInitiationType {
+  USER_INITIATED = 1,
+  RENDERER_INITIATED = 2,
+};
+
 // Implementation of NavigationManager.
 // Generally mirrors upstream's NavigationController.
 class NavigationManagerImpl : public NavigationManager {
  public:
   NavigationManagerImpl();
   ~NavigationManagerImpl() override;
 
   // Setters for NavigationManagerDelegate and BrowserState.
   void SetDelegate(NavigationManagerDelegate* delegate);
   void SetBrowserState(BrowserState* browser_state);
@@ skipping 36 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 new item with the given url, referrer, navigation type, pending item
+  // type, making it the current item. If pending item is the same as the

[Eugene But (OOO till 7-30), 2017/02/17 00:00:23]

s/current/pending

[liaoyuke, 2017/02/17 01:16:51]

Done.

+  // 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,
+                      ItemInitiationType initiation_type);
+
   // Convenience accessors to get the underlying NavigationItems from the
   // SessionEntries returned from |session_controller_|'s -lastUserEntry and
   // -previousEntry methods.
   // TODO(crbug.com/546365): Remove these methods.
   NavigationItem* GetLastUserItem() const;
   NavigationItem* GetPreviousItem() const;
 
   // Temporary method. Returns a vector of NavigationItems corresponding to
   // the SessionEntries of the uderlying CRWSessionController.
   // TODO(crbug.com/546365): Remove this method.
@@ skipping 17 matching lines @@
   int GetPendingItemIndex() const override;
   int GetLastCommittedItemIndex() const override;
   bool RemoveItemAtIndex(int index) override;
   bool CanGoBack() const override;
   bool CanGoForward() const override;
   bool CanGoToOffset(int offset) const override;
   void GoBack() override;
   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.
   // TODO(crbug.com/546197): remove once NavigationItem creation occurs in this
   // class.
   std::unique_ptr<std::vector<BrowserURLRewriter::URLRewriter>>
   GetTransientURLRewriters();
 
   // Called to reset the transient url rewriter list.
   void RemoveTransientURLRewriters();
@@ skipping 11 matching lines @@
 
  private:
   // The SessionStorageBuilder functions require access to private variables of
   // NavigationManagerImpl.
   friend SessionStorageBuilder;
 
   // Returns true if the PageTransition for the underlying navigation item at
   // |index| has ui::PAGE_TRANSITION_IS_REDIRECT_MASK.
   bool IsRedirectItemAtIndex(int index) const;
 
+  // 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_;
 
   // The BrowserState that is associated with this instance.
   BrowserState* browser_state_;
 
   // CRWSessionController that backs this instance.
   // TODO(stuartmorgan): Fold CRWSessionController into this class.
   base::scoped_nsobject<CRWSessionController> session_controller_;
 
   // Weak pointer to the facade delegate.
   NavigationManagerFacadeDelegate* facade_delegate_;
 
   // 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_