[Navigation Experiment] Add WKBasedNavigationManagerImpl.

ios/web/navigation/wk_based_navigation_manager_impl.h

+// Copyright 2017 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_WK_BASED_NAVIGATION_MANAGER_IMPL_H_
+#define IOS_WEB_NAVIGATION_WK_BASED_NAVIGATION_MANAGER_IMPL_H_
+
+#include <stddef.h>
+
+#include <memory>
+#include <vector>
+
+#import "base/mac/scoped_nsobject.h"
+#include "base/macros.h"
+#import "ios/web/navigation/navigation_item_impl.h"
+#import "ios/web/navigation/navigation_manager_impl.h"
+#include "ios/web/public/reload_type.h"
+#include "ui/base/page_transition_types.h"
+#include "url/gurl.h"
+
+namespace web {
+class BrowserState;
+class NavigationItem;
+struct Referrer;
+class NavigationManagerDelegate;
+class SessionStorageBuilder;
+
+// WKBackForwardList based implementation of NavigationManagerImpl.
+class WKBasedNavigationManagerImpl : public NavigationManagerImpl {
+ public:
+  WKBasedNavigationManagerImpl();
+  ~WKBasedNavigationManagerImpl() override;
+
+  // NavigationManagerImpl:
+  void SetDelegate(NavigationManagerDelegate* delegate) override;
+  void SetBrowserState(BrowserState* browser_state) override;
+  void SetSessionController(CRWSessionController* session_controller) override;
+  void InitializeSession() override;
+  void ReplaceSessionHistory(std::vector<std::unique_ptr<NavigationItem>> items,
+                             int current_index) override;
+  void OnNavigationItemsPruned(size_t pruned_item_count) override;
+  void OnNavigationItemChanged() override;
+  void OnNavigationItemCommitted() override;
+  CRWSessionController* GetSessionController() const override;
+  void AddTransientItem(const GURL& url) override;
+  void AddPendingItem(
+      const GURL& url,
+      const web::Referrer& referrer,
+      ui::PageTransition navigation_type,
+      NavigationInitiationType initiation_type,
+      UserAgentOverrideOption user_agent_override_option) override;
+  void CommitPendingItem() override;
+  std::unique_ptr<std::vector<BrowserURLRewriter::URLRewriter>>
+  GetTransientURLRewriters() override;
+  void RemoveTransientURLRewriters() override;
+  int GetIndexForOffset(int offset) const override;
+  int GetPreviousItemIndex() const override;
+
+  // NavigationManager:
+  BrowserState* GetBrowserState() const override;
+  WebState* GetWebState() const override;
+  NavigationItem* GetVisibleItem() const override;
+  NavigationItem* GetLastCommittedItem() const override;
+  NavigationItem* GetPendingItem() const override;
+  NavigationItem* GetTransientItem() const override;
+  void DiscardNonCommittedItems() override;
+  void LoadURLWithParams(const NavigationManager::WebLoadParams&) override;
+  void AddTransientURLRewriter(
+      BrowserURLRewriter::URLRewriter rewriter) override;
+  int GetItemCount() const override;
+  NavigationItem* GetItemAtIndex(size_t index) const override;
+  int GetIndexOfItem(const NavigationItem* item) const override;
+  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(ReloadType reload_type, bool check_for_reposts) override;
+  NavigationItemList GetBackwardItems() const override;
+  NavigationItemList GetForwardItems() const override;
+  void CopyStateFromAndPrune(const NavigationManager* source) override;
+  bool CanPruneAllButLastCommittedItem() const override;
+
+ private:
+  // The SessionStorageBuilder functions require access to private variables of
+  // NavigationManagerImpl.
+  friend SessionStorageBuilder;
+
+  // NavigationManagerImpl methods used by SessionStorageBuilder.
+  NavigationItemImpl* GetNavigationItemImplAtIndex(size_t index) const override;
+
+  // Current item is the anchor of the navigation history.
+  // int GetCurrentItemIndex() const;
+  // NavigationItem* GetCurrentItem() const;
+
+  // Sync navigation_items_ to WKBackForwardList. This should be no-op in most
+  // cases, but will do real work after a renderer-initiated navigation.
+  // This method guarantees the navigation_items_ invariant.
+  // Returns true if committed_navigation_items_ were updated; false if no-op.
+  bool SyncNavigationItems() const;
+
+  // The primary delegate for this manager.
+  NavigationManagerDelegate* delegate_;
+
+  // The BrowserState that is associated with this instance.
+  BrowserState* browser_state_;
+
+  // List of transient url rewriters added by |AddTransientURLRewriter()|.
+  std::unique_ptr<std::vector<BrowserURLRewriter::URLRewriter>>
+      transient_url_rewriters_;
+
+  // NavigationItemImpl objects associated with the back/forward history.
+  // Invariant:
+  //   navigation_items_.size() == GetItemCount() == backList.count +
+  //   forwardList.count + currentItem ? 1 : 0.
+  mutable std::vector<std::unique_ptr<NavigationItemImpl>>
+      committed_navigation_items_;
+
+  std::unique_ptr<NavigationItemImpl> pending_item_;
+  std::unique_ptr<NavigationItemImpl> transient_item_;
+
+  DISALLOW_COPY_AND_ASSIGN(WKBasedNavigationManagerImpl);
+};
+
+}  // namespace web
+
+#endif  // IOS_WEB_NAVIGATION_WK_BASED_NAVIGATION_MANAGER_IMPL_H_